{"id":12855,"date":"2025-01-06T16:23:39","date_gmt":"2025-01-06T08:23:39","guid":{"rendered":"http:\/\/www.aiersheng.cc\/?p=12855"},"modified":"2025-01-06T16:40:20","modified_gmt":"2025-01-06T08:40:20","slug":"sql-%e7%ae%80%e4%bb%8b%e4%b8%8e%e8%af%a6%e7%bb%86%e8%af%ad%e6%b3%95%e8%a7%a3%e6%9e%90","status":"publish","type":"post","link":"https:\/\/www.aiersheng.cc\/?p=12855","title":{"rendered":"SQL \u7b80\u4ecb\u4e0e\u8be6\u7ec6\u8bed\u6cd5\u89e3\u6790"},"content":{"rendered":"<h3>SQL \u7b80\u4ecb<\/h3>\n<p><strong>SQL<\/strong>\uff08\u7ed3\u6784\u5316\u67e5\u8be2\u8bed\u8a00\uff0cStructured Query Language\uff09\u662f\u4e00\u79cd\u7528\u4e8e\u7ba1\u7406\u548c\u64cd\u4f5c\u5173\u7cfb\u578b\u6570\u636e\u5e93\u7684\u6807\u51c6\u8bed\u8a00\u3002\u5b83\u88ab\u5e7f\u6cdb\u5e94\u7528\u4e8e\u5404\u7c7b\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\uff08\u5982 MySQL\u3001Oracle\u3001SQL Server\u3001PostgreSQL\u3001SQLite \u7b49\uff09\u4e2d\u3002SQL \u4f7f\u5f97\u5f00\u53d1\u8005\u53ef\u4ee5\u901a\u8fc7\u7b80\u5355\u7684\u547d\u4ee4\u5bf9\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u8fdb\u884c\u67e5\u8be2\u3001\u63d2\u5165\u3001\u66f4\u65b0\u548c\u5220\u9664\u7b49\u64cd\u4f5c\u3002<\/p>\n<h4>SQL \u7684\u4f5c\u7528\uff1a<\/h4>\n<ul>\n<li><strong>\u67e5\u8be2\u6570\u636e<\/strong>\uff1a\u4ece\u6570\u636e\u5e93\u4e2d\u68c0\u7d22\u6570\u636e\u3002<\/li>\n<li><strong>\u63d2\u5165\u3001\u66f4\u65b0\u548c\u5220\u9664\u6570\u636e<\/strong>\uff1a\u5bf9\u6570\u636e\u5e93\u4e2d\u7684\u8bb0\u5f55\u8fdb\u884c\u4fee\u6539\u3002<\/li>\n<li><strong>\u6570\u636e\u5e93\u7ba1\u7406<\/strong>\uff1a\u521b\u5efa\u3001\u4fee\u6539\u548c\u5220\u9664\u6570\u636e\u5e93\u3001\u8868\u3001\u89c6\u56fe\u7b49\u6570\u636e\u5e93\u5bf9\u8c61\u3002<\/li>\n<li><strong>\u6743\u9650\u63a7\u5236<\/strong>\uff1a\u6388\u4e88\u6216\u64a4\u9500\u7528\u6237\u5bf9\u6570\u636e\u5e93\u7684\u8bbf\u95ee\u6743\u9650\u3002<\/li>\n<\/ul>\n<p>SQL \u662f\u5173\u7cfb\u578b\u6570\u636e\u5e93\u7684\u6838\u5fc3\u8bed\u8a00\uff0c\u80fd\u591f\u5e2e\u52a9\u5f00\u53d1\u8005\u9ad8\u6548\u7ba1\u7406\u548c\u64cd\u63a7\u6570\u636e\u3002\u901a\u8fc7 SQL\uff0c\u7528\u6237\u4e0d\u4ec5\u80fd\u6267\u884c\u5e38\u89c1\u7684 CRUD\uff08\u589e\u3001\u5220\u3001\u6539\u3001\u67e5\uff09\u64cd\u4f5c\uff0c\u8fd8\u80fd\u8fdb\u884c\u66f4\u590d\u6742\u7684\u6570\u636e\u5206\u6790\u3001\u4e8b\u52a1\u7ba1\u7406\u3001\u6743\u9650\u63a7\u5236\u7b49\u64cd\u4f5c\u3002<\/p>\n<hr \/>\n<h3>SQL \u8bed\u6cd5<\/h3>\n<p>SQL \u8bed\u6cd5\u6d89\u53ca\u591a\u79cd\u8bed\u53e5\uff0c\u6309\u529f\u80fd\u53ef\u4ee5\u5206\u4e3a\u4ee5\u4e0b\u51e0\u7c7b\uff1a<\/p>\n<h4>1. \u6570\u636e\u67e5\u8be2\u8bed\u8a00\uff08DQL\uff09<\/h4>\n<p>\u6570\u636e\u67e5\u8be2\u8bed\u8a00\u4e3b\u8981\u7528\u4e8e\u4ece\u6570\u636e\u5e93\u4e2d\u67e5\u8be2\u6570\u636e\uff0c\u5e38\u7528\u7684 DQL \u547d\u4ee4\u5c31\u662f <code>SELECT<\/code>\u3002<\/p>\n<h5><strong>SELECT \u8bed\u53e5<\/strong><\/h5>\n<p><code>SELECT<\/code> \u662f SQL \u4e2d\u6700\u5e38\u7528\u7684\u67e5\u8be2\u8bed\u53e5\uff0c\u5141\u8bb8\u7528\u6237\u4ece\u4e00\u4e2a\u6216\u591a\u4e2a\u8868\u4e2d\u63d0\u53d6\u6570\u636e\u3002\u5b83\u7684\u57fa\u672c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> column1, column2, ...<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> table_name;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u89e3\u91ca\uff1a<\/strong><\/p>\n<ul>\n<li><code>SELECT<\/code>\uff1a\u6307\u5b9a\u8981\u67e5\u8be2\u7684\u5217\u3002<\/li>\n<li><code>FROM<\/code>\uff1a\u6307\u5b9a\u6570\u636e\u6765\u6e90\u7684\u8868\u3002<\/li>\n<\/ul>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u67e5\u8be2 <code>employees<\/code> \u8868\u4e2d\u7684\u6240\u6709\u5217\u6570\u636e\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-operator\">*<\/span> <span class=\"hljs-keyword\">FROM<\/span> employees;<br \/>\n<\/code><\/div>\n<\/div>\n<p>\u67e5\u8be2 <code>employees<\/code> \u8868\u4e2d <code>name<\/code> \u548c <code>salary<\/code> \u4e24\u5217\u7684\u6570\u636e\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> name, salary <span class=\"hljs-keyword\">FROM<\/span> employees;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>WHERE \u5b50\u53e5<\/strong><\/h5>\n<p><code>WHERE<\/code> \u5b50\u53e5\u7528\u4e8e\u5bf9\u67e5\u8be2\u7684\u7ed3\u679c\u8fdb\u884c\u8fc7\u6ee4\uff0c\u53ea\u8fd4\u56de\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u3002\u5b83\u7528\u4e8e\u6307\u5b9a\u6761\u4ef6\u8bed\u53e5\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> column1, column2<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> table_name<br \/>\n<span class=\"hljs-keyword\">WHERE<\/span> <span class=\"hljs-keyword\">condition<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u67e5\u8be2\u6240\u6709 <code>salary<\/code> \u5927\u4e8e 50000 \u7684\u5458\u5de5\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> name, salary<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> employees<br \/>\n<span class=\"hljs-keyword\">WHERE<\/span> salary <span class=\"hljs-operator\">&gt;<\/span> <span class=\"hljs-number\">50000<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>ORDER BY \u5b50\u53e5<\/strong><\/h5>\n<p><code>ORDER BY<\/code> \u5b50\u53e5\u7528\u4e8e\u5bf9\u67e5\u8be2\u7ed3\u679c\u6309\u6307\u5b9a\u5217\u8fdb\u884c\u6392\u5e8f\uff0c\u9ed8\u8ba4\u5347\u5e8f\u6392\u5217\u3002\u5982\u679c\u60f3\u8981\u964d\u5e8f\u6392\u5217\uff0c\u4f7f\u7528 <code>DESC<\/code>\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> column1, column2<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> table_name<br \/>\n<span class=\"hljs-keyword\">ORDER<\/span> <span class=\"hljs-keyword\">BY<\/span> column1 [<span class=\"hljs-keyword\">ASC<\/span> <span class=\"hljs-operator\">|<\/span> <span class=\"hljs-keyword\">DESC<\/span>];<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u67e5\u8be2 <code>employees<\/code> \u8868\uff0c\u6309 <code>salary<\/code> \u964d\u5e8f\u6392\u5217\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> name, salary<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> employees<br \/>\n<span class=\"hljs-keyword\">ORDER<\/span> <span class=\"hljs-keyword\">BY<\/span> salary <span class=\"hljs-keyword\">DESC<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>LIMIT \u5b50\u53e5<\/strong><\/h5>\n<p><code>LIMIT<\/code> \u7528\u4e8e\u9650\u5236\u8fd4\u56de\u7684\u7ed3\u679c\u884c\u6570\u3002\u5b83\u5e38\u7528\u4e8e\u5206\u9875\u67e5\u8be2\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> column1, column2<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> table_name<br \/>\nLIMIT number;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u67e5\u8be2 <code>employees<\/code> \u8868\u4e2d\u7684\u524d 5 \u884c\u6570\u636e\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-operator\">*<\/span> <span class=\"hljs-keyword\">FROM<\/span> employees<br \/>\nLIMIT <span class=\"hljs-number\">5<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<hr \/>\n<h4>2. \u6570\u636e\u5b9a\u4e49\u8bed\u8a00\uff08DDL\uff09<\/h4>\n<p>\u6570\u636e\u5b9a\u4e49\u8bed\u8a00\u7528\u4e8e\u5b9a\u4e49\u6570\u636e\u5e93\u4e2d\u7684\u7ed3\u6784\uff0c\u8bf8\u5982\u521b\u5efa\u3001\u4fee\u6539\u6216\u5220\u9664\u8868\u7b49\u64cd\u4f5c\u3002<\/p>\n<h5><strong>CREATE DATABASE<\/strong><\/h5>\n<p><code>CREATE DATABASE<\/code> \u7528\u4e8e\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u6570\u636e\u5e93\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">CREATE<\/span> DATABASE database_name;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u521b\u5efa\u4e00\u4e2a\u540d\u4e3a <code>company_db<\/code> \u7684\u6570\u636e\u5e93\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">CREATE<\/span> DATABASE company_db;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>CREATE TABLE<\/strong><\/h5>\n<p><code>CREATE TABLE<\/code> \u7528\u4e8e\u521b\u5efa\u65b0\u7684\u8868\uff0c\u5e76\u5b9a\u4e49\u8868\u7684\u5217\u53ca\u5176\u6570\u636e\u7c7b\u578b\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">CREATE<\/span> <span class=\"hljs-keyword\">TABLE<\/span> table_name (<br \/>\n    column1 datatype,<br \/>\n    column2 datatype,<br \/>\n    ...<br \/>\n);<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u521b\u5efa\u4e00\u4e2a <code>employees<\/code> \u8868\uff0c\u5305\u542b <code>id<\/code>, <code>name<\/code>, <code>salary<\/code> \u7b49\u5b57\u6bb5\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">CREATE<\/span> <span class=\"hljs-keyword\">TABLE<\/span> employees (<br \/>\n    id <span class=\"hljs-type\">INT<\/span> <span class=\"hljs-keyword\">PRIMARY<\/span> KEY,<br \/>\n    name <span class=\"hljs-type\">VARCHAR<\/span>(<span class=\"hljs-number\">100<\/span>),<br \/>\n    salary <span class=\"hljs-type\">DECIMAL<\/span>(<span class=\"hljs-number\">10<\/span>, <span class=\"hljs-number\">2<\/span>)<br \/>\n);<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>ALTER TABLE<\/strong><\/h5>\n<p><code>ALTER TABLE<\/code> \u7528\u4e8e\u4fee\u6539\u8868\u7684\u7ed3\u6784\uff0c\u5982\u6dfb\u52a0\u3001\u5220\u9664\u6216\u4fee\u6539\u5217\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">ALTER<\/span> <span class=\"hljs-keyword\">TABLE<\/span> table_name<br \/>\n<span class=\"hljs-keyword\">ADD<\/span> column_name datatype;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u5728 <code>employees<\/code> \u8868\u4e2d\u6dfb\u52a0 <code>address<\/code> \u5217\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">ALTER<\/span> <span class=\"hljs-keyword\">TABLE<\/span> employees<br \/>\n<span class=\"hljs-keyword\">ADD<\/span> address <span class=\"hljs-type\">VARCHAR<\/span>(<span class=\"hljs-number\">255<\/span>);<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>DROP TABLE<\/strong><\/h5>\n<p><code>DROP TABLE<\/code> \u7528\u4e8e\u5220\u9664\u4e00\u4e2a\u8868\u53ca\u5176\u6570\u636e\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">DROP<\/span> <span class=\"hljs-keyword\">TABLE<\/span> table_name;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u5220\u9664 <code>employees<\/code> \u8868\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">DROP<\/span> <span class=\"hljs-keyword\">TABLE<\/span> employees;<br \/>\n<\/code><\/div>\n<\/div>\n<hr \/>\n<h4>3. \u6570\u636e\u64cd\u4f5c\u8bed\u8a00\uff08DML\uff09<\/h4>\n<p>\u6570\u636e\u64cd\u4f5c\u8bed\u8a00\u7528\u4e8e\u64cd\u4f5c\u8868\u4e2d\u7684\u6570\u636e\uff0c\u4e3b\u8981\u5305\u62ec\u63d2\u5165\u3001\u66f4\u65b0\u548c\u5220\u9664\u8bb0\u5f55\u3002<\/p>\n<h5><strong>INSERT INTO<\/strong><\/h5>\n<p><code>INSERT INTO<\/code> \u7528\u4e8e\u5411\u8868\u4e2d\u63d2\u5165\u65b0\u8bb0\u5f55\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">INSERT<\/span> <span class=\"hljs-keyword\">INTO<\/span> table_name (column1, column2, ...)<br \/>\n<span class=\"hljs-keyword\">VALUES<\/span> (value1, value2, ...);<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u5411 <code>employees<\/code> \u8868\u63d2\u5165\u4e00\u6761\u8bb0\u5f55\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">INSERT<\/span> <span class=\"hljs-keyword\">INTO<\/span> employees (id, name, salary)<br \/>\n<span class=\"hljs-keyword\">VALUES<\/span> (<span class=\"hljs-number\">1<\/span>, <span class=\"hljs-string\">'Alice'<\/span>, <span class=\"hljs-number\">50000<\/span>);<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>UPDATE<\/strong><\/h5>\n<p><code>UPDATE<\/code> \u7528\u4e8e\u4fee\u6539\u8868\u4e2d\u73b0\u6709\u8bb0\u5f55\u7684\u503c\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">UPDATE<\/span> table_name<br \/>\n<span class=\"hljs-keyword\">SET<\/span> column1 <span class=\"hljs-operator\">=<\/span> value1, column2 <span class=\"hljs-operator\">=<\/span> value2, ...<br \/>\n<span class=\"hljs-keyword\">WHERE<\/span> <span class=\"hljs-keyword\">condition<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u5c06 <code>Alice<\/code> \u7684\u5de5\u8d44\u66f4\u65b0\u4e3a 60000\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">UPDATE<\/span> employees<br \/>\n<span class=\"hljs-keyword\">SET<\/span> salary <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-number\">60000<\/span><br \/>\n<span class=\"hljs-keyword\">WHERE<\/span> name <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">'Alice'<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>DELETE<\/strong><\/h5>\n<p><code>DELETE<\/code> \u7528\u4e8e\u5220\u9664\u8868\u4e2d\u7684\u4e00\u6761\u6216\u591a\u6761\u8bb0\u5f55\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">DELETE<\/span> <span class=\"hljs-keyword\">FROM<\/span> table_name<br \/>\n<span class=\"hljs-keyword\">WHERE<\/span> <span class=\"hljs-keyword\">condition<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u5220\u9664\u6240\u6709\u5de5\u8d44\u4f4e\u4e8e 30000 \u7684\u5458\u5de5\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">DELETE<\/span> <span class=\"hljs-keyword\">FROM<\/span> employees<br \/>\n<span class=\"hljs-keyword\">WHERE<\/span> salary <span class=\"hljs-operator\">&lt;<\/span> <span class=\"hljs-number\">30000<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<hr \/>\n<h4>4. \u6570\u636e\u63a7\u5236\u8bed\u8a00\uff08DCL\uff09<\/h4>\n<p>\u6570\u636e\u63a7\u5236\u8bed\u8a00\u7528\u4e8e\u63a7\u5236\u6570\u636e\u5e93\u7528\u6237\u7684\u8bbf\u95ee\u6743\u9650\u3002<\/p>\n<h5><strong>GRANT<\/strong><\/h5>\n<p><code>GRANT<\/code> \u7528\u4e8e\u6388\u4e88\u6570\u636e\u5e93\u7528\u6237\u6743\u9650\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">GRANT<\/span> privilege_type <span class=\"hljs-keyword\">ON<\/span> object <span class=\"hljs-keyword\">TO<\/span> <span class=\"hljs-keyword\">user<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u6388\u4e88\u7528\u6237 <code>john<\/code> \u5bf9 <code>employees<\/code> \u8868\u7684 <code>SELECT<\/code> \u6743\u9650\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">GRANT<\/span> <span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-keyword\">ON<\/span> employees <span class=\"hljs-keyword\">TO<\/span> john;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>REVOKE<\/strong><\/h5>\n<p><code>REVOKE<\/code> \u7528\u4e8e\u64a4\u9500\u4e4b\u524d\u6388\u4e88\u7528\u6237\u7684\u6743\u9650\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">REVOKE<\/span> privilege_type <span class=\"hljs-keyword\">ON<\/span> object <span class=\"hljs-keyword\">FROM<\/span> <span class=\"hljs-keyword\">user<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u64a4\u9500\u7528\u6237 <code>john<\/code> \u5bf9 <code>employees<\/code> \u8868\u7684 <code>SELECT<\/code> \u6743\u9650\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">REVOKE<\/span> <span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-keyword\">ON<\/span> employees <span class=\"hljs-keyword\">FROM<\/span> john;<br \/>\n<\/code><\/div>\n<\/div>\n<hr \/>\n<h4>5. \u4e8b\u52a1\u63a7\u5236\u8bed\u8a00\uff08TCL\uff09<\/h4>\n<p>\u4e8b\u52a1\u63a7\u5236\u8bed\u8a00\u7528\u4e8e\u63a7\u5236\u4e8b\u52a1\u7684\u6267\u884c\uff0c\u786e\u4fdd\u6570\u636e\u7684\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u3002<\/p>\n<h5><strong>COMMIT<\/strong><\/h5>\n<p><code>COMMIT<\/code> \u7528\u4e8e\u63d0\u4ea4\u4e8b\u52a1\uff0c\u4f7f\u4e8b\u52a1\u4e2d\u7684\u6240\u6709\u64cd\u4f5c\u751f\u6548\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">COMMIT<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u63d0\u4ea4\u4e00\u4e2a\u4e8b\u52a1\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">COMMIT<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>ROLLBACK<\/strong><\/h5>\n<p><code>ROLLBACK<\/code> \u7528\u4e8e\u56de\u6eda\u4e8b\u52a1\uff0c\u64a4\u9500\u4e8b\u52a1\u4e2d\u7684\u6240\u6709\u64cd\u4f5c\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">ROLLBACK<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u56de\u6eda\u4e00\u4e2a\u4e8b\u52a1\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">ROLLBACK<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h5><strong>SAVEPOINT<\/strong><\/h5>\n<p><code>SAVEPOINT<\/code> \u7528\u4e8e\u8bbe\u7f6e\u4e00\u4e2a\u4fdd\u5b58\u70b9\uff0c\u5141\u8bb8\u5728\u4e8b\u52a1\u4e2d\u90e8\u5206\u56de\u6eda\u3002<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SAVEPOINT<\/span> savepoint_name;<br \/>\n<\/code><\/div>\n<\/div>\n<p><strong>\u793a\u4f8b\uff1a<\/strong> \u8bbe\u7f6e\u4e00\u4e2a\u4fdd\u5b58\u70b9\uff1a<\/p>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SAVEPOINT<\/span> savepoint1;<br \/>\n<\/code><\/div>\n<\/div>\n<hr \/>\n<h3>\u5e38\u89c1 SQL \u8bed\u53e5\u793a\u4f8b<\/h3>\n<h4>1. \u67e5\u8be2\u6240\u6709\u8bb0\u5f55\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-operator\">*<\/span> <span class=\"hljs-keyword\">FROM<\/span> employees;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>2. \u67e5\u8be2\u7279\u5b9a\u5217\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> name, salary <span class=\"hljs-keyword\">FROM<\/span> employees;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>3. \u4f7f\u7528\u6761\u4ef6\u67e5\u8be2\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-operator\">*<\/span> <span class=\"hljs-keyword\">FROM<\/span> employees <span class=\"hljs-keyword\">WHERE<\/span> salary <span class=\"hljs-operator\">&gt;<\/span> <span class=\"hljs-number\">50000<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>4. \u6392\u5e8f\u67e5\u8be2\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> name, salary <span class=\"hljs-keyword\">FROM<\/span> employees <span class=\"hljs-keyword\">ORDER<\/span> <span class=\"hljs-keyword\">BY<\/span> salary <span class=\"hljs-keyword\">DESC<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>5. \u4f7f\u7528\u805a\u5408\u51fd\u6570\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> <span class=\"hljs-built_in\">AVG<\/span>(salary) <span class=\"hljs-keyword\">FROM<\/span> employees;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>6. \u591a\u8868\u8fde\u63a5\u67e5\u8be2\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">SELECT<\/span> employees.name, departments.name<br \/>\n<span class=\"hljs-keyword\">FROM<\/span> employees<br \/>\n<span class=\"hljs-keyword\">INNER<\/span> <span class=\"hljs-keyword\">JOIN<\/span> departments <span class=\"hljs-keyword\">ON<\/span> employees.department_id <span class=\"hljs-operator\">=<\/span> departments.id;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>7. \u63d2\u5165\u6570\u636e\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">INSERT<\/span> <span class=\"hljs-keyword\">INTO<\/span> employees (name, age, salary)<br \/>\n<span class=\"hljs-keyword\">VALUES<\/span> (<span class=\"hljs-string\">'Bob'<\/span>, <span class=\"hljs-number\">28<\/span>, <span class=\"hljs-number\">45000<\/span>);<br \/>\n<\/code><\/div>\n<\/div>\n<h4>8. \u66f4\u65b0\u6570\u636e\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">UPDATE<\/span> employees <span class=\"hljs-keyword\">SET<\/span> salary <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-number\">60000<\/span> <span class=\"hljs-keyword\">WHERE<\/span> name <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">'Alice'<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<h4>9. \u5220\u9664\u6570\u636e\uff1a<\/h4>\n<div class=\"contain-inline-size rounded-md border-[0.5px] border-token-border-medium relative bg-token-sidebar-surface-primary dark:bg-gray-950\">\n<div class=\"flex items-center text-token-text-secondary px-4 py-2 text-xs font-sans justify-between rounded-t-md h-9 bg-token-sidebar-surface-primary dark:bg-token-main-surface-secondary select-none\">sql<\/div>\n<div class=\"sticky top-9 md:top-[5.75rem]\">\n<div class=\"absolute bottom-0 right-2 flex h-9 items-center\">\n<div class=\"flex items-center rounded bg-token-sidebar-surface-primary px-2 font-sans text-xs text-token-text-secondary dark:bg-token-main-surface-secondary\"><span class=\"\" data-state=\"closed\"><button class=\"flex gap-1 items-center select-none py-1\" aria-label=\"\u590d\u5236\">\u590d\u5236\u4ee3\u7801<\/button><\/span><\/div>\n<\/div>\n<\/div>\n<div class=\"overflow-y-auto p-4\" dir=\"ltr\"><code class=\"!whitespace-pre hljs language-sql\"><span class=\"hljs-keyword\">DELETE<\/span> <span class=\"hljs-keyword\">FROM<\/span> employees <span class=\"hljs-keyword\">WHERE<\/span> name <span class=\"hljs-operator\">=<\/span> <span class=\"hljs-string\">'Bob'<\/span>;<br \/>\n<\/code><\/div>\n<\/div>\n<hr \/>\n<h3>\u603b\u7ed3<\/h3>\n<p>SQL \u662f\u4e00\u79cd\u529f\u80fd\u5f3a\u5927\u7684\u67e5\u8be2\u8bed\u8a00\uff0c\u5e7f\u6cdb\u7528\u4e8e\u7ba1\u7406\u5173\u7cfb\u578b\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u3002SQL \u7684\u8bed\u6cd5\u7b80\u6d01\u4e14\u76f4\u89c2\uff0c\u80fd\u9ad8\u6548\u5730\u8fdb\u884c\u6570\u636e\u67e5\u8be2\u3001\u63d2\u5165\u3001\u66f4\u65b0\u548c\u5220\u9664\u7b49\u64cd\u4f5c\u3002\u6b64\u5916\uff0cSQL \u4e5f\u5141\u8bb8\u5f00\u53d1\u8005\u7ba1\u7406\u6570\u636e\u5e93\u7ed3\u6784\u3001\u63a7\u5236\u6743\u9650\u4ee5\u53ca\u4fdd\u8bc1\u6570\u636e\u4e00\u81f4\u6027\u548c\u5b8c\u6574\u6027\u3002\u638c\u63e1 SQL \u8bed\u8a00\u662f\u4efb\u4f55\u6570\u636e\u5e93\u5f00\u53d1\u4eba\u5458\u6216\u6570\u636e\u5206\u6790\u4eba\u5458\u5fc5\u4e0d\u53ef\u5c11\u7684\u6280\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>SQL \u7b80\u4ecb SQL\uff08\u7ed3\u6784\u5316\u67e5\u8be2\u8bed\u8a00\uff0cS&#8230;<\/p>\n","protected":false},"author":1,"featured_media":12857,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[68],"tags":[],"class_list":["post-12855","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-zzjy"],"_links":{"self":[{"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=\/wp\/v2\/posts\/12855","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=12855"}],"version-history":[{"count":0,"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=\/wp\/v2\/posts\/12855\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=\/wp\/v2\/media\/12857"}],"wp:attachment":[{"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=12855"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=12855"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.aiersheng.cc\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=12855"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}