{"id":168477,"date":"2024-11-06T12:42:26","date_gmt":"2024-11-06T04:42:26","guid":{"rendered":"https:\/\/server.hk\/cnblog\/168477\/"},"modified":"2024-11-06T12:42:27","modified_gmt":"2024-11-06T04:42:27","slug":"sql-%e8%aa%9e%e8%a8%80%e5%bf%ab%e9%80%9f%e5%85%a5%e9%96%80%ef%bc%88%e4%ba%8c%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/168477\/","title":{"rendered":"SQL \u8a9e\u8a00\u5feb\u901f\u5165\u9580\uff08\u4e8c\uff09"},"content":{"rendered":"<h1 id=\"sql-%e8%aa%9e%e8%a8%80%e5%bf%ab%e9%80%9f%e5%85%a5%e9%96%80%ef%bc%88%e4%ba%8c%ef%bc%89-yjRCaAIbEA\">SQL \u8a9e\u8a00\u5feb\u901f\u5165\u9580\uff08\u4e8c\uff09<\/h1>\n<p>\u5728\u4e0a\u4e00\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u5011\u4ecb\u7d39\u4e86 SQL \u8a9e\u8a00\u7684\u57fa\u672c\u6982\u5ff5\u548c\u4e00\u4e9b\u5e38\u7528\u7684\u67e5\u8a62\u8a9e\u53e5\u3002\u672c\u7bc7\u6587\u7ae0\u5c07\u9032\u4e00\u6b65\u63a2\u8a0e SQL \u7684\u9032\u968e\u529f\u80fd\uff0c\u5305\u62ec\u8cc7\u6599\u7684\u66f4\u65b0\u3001\u522a\u9664\u4ee5\u53ca\u5982\u4f55\u4f7f\u7528\u805a\u5408\u51fd\u6578\u4f86\u9032\u884c\u6578\u64da\u5206\u6790\u3002<\/p>\n<h2 id=\"%e8%b3%87%e6%96%99%e6%9b%b4%e6%96%b0-yjRCaAIbEA\">\u8cc7\u6599\u66f4\u65b0<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u66f4\u65b0\u8cc7\u6599\u7684\u4e3b\u8981\u8a9e\u53e5\u662f <code>UPDATE<\/code>\u3002\u9019\u500b\u8a9e\u53e5\u5141\u8a31\u7528\u6236\u4fee\u6539\u8cc7\u6599\u8868\u4e2d\u7684\u73fe\u6709\u8a18\u9304\u3002\u4ee5\u4e0b\u662f <code>UPDATE<\/code> \u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>UPDATE \u8868\u540d\nSET \u6b04\u4f4d1 = \u503c1, \u6b04\u4f4d2 = \u503c2, ...\nWHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>employees<\/code> \u7684\u8868\u683c\uff0c\u4e26\u4e14\u6211\u5011\u60f3\u8981\u66f4\u65b0\u67d0\u4f4d\u54e1\u5de5\u7684\u85aa\u6c34\uff1a<\/p>\n<pre><code>UPDATE employees\nSET salary = 60000\nWHERE employee_id = 1;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u5c07\u54e1\u5de5 ID \u70ba 1 \u7684\u85aa\u6c34\u66f4\u65b0\u70ba 60000\u3002\u8acb\u6ce8\u610f\uff0c<code>WHERE<\/code> \u5b50\u53e5\u662f\u975e\u5e38\u91cd\u8981\u7684\uff0c\u56e0\u70ba\u5982\u679c\u7701\u7565\u5b83\uff0c\u5c07\u6703\u66f4\u65b0\u8868\u4e2d\u6240\u6709\u7684\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e8%b3%87%e6%96%99%e5%88%aa%e9%99%a4-yjRCaAIbEA\">\u8cc7\u6599\u522a\u9664<\/h2>\n<p>\u522a\u9664\u8cc7\u6599\u7684\u4e3b\u8981\u8a9e\u53e5\u662f <code>DELETE<\/code>\u3002\u9019\u500b\u8a9e\u53e5\u7528\u65bc\u5f9e\u8cc7\u6599\u8868\u4e2d\u522a\u9664\u4e00\u689d\u6216\u591a\u689d\u8a18\u9304\u3002\u4ee5\u4e0b\u662f <code>DELETE<\/code> \u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>DELETE FROM \u8868\u540d\nWHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u5982\u679c\u6211\u5011\u60f3\u8981\u522a\u9664\u54e1\u5de5 ID \u70ba 1 \u7684\u8a18\u9304\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u8a9e\u53e5\uff1a<\/p>\n<pre><code>DELETE FROM employees\nWHERE employee_id = 1;<\/code><\/pre>\n<p>\u540c\u6a23\u5730\uff0c<code>WHERE<\/code> \u5b50\u53e5\u5728\u9019\u88e1\u4e5f\u975e\u5e38\u91cd\u8981\uff0c\u56e0\u70ba\u5982\u679c\u7701\u7565\u5b83\uff0c\u5c07\u6703\u522a\u9664\u8868\u4e2d\u6240\u6709\u7684\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b8-yjRCaAIbEA\">\u805a\u5408\u51fd\u6578<\/h2>\n<p>SQL \u63d0\u4f9b\u4e86\u591a\u7a2e\u805a\u5408\u51fd\u6578\u4f86\u9032\u884c\u6578\u64da\u5206\u6790\uff0c\u6700\u5e38\u7528\u7684\u5305\u62ec <code>COUNT<\/code>\u3001<code>SUM<\/code>\u3001<code>AVG<\/code>\u3001<code>MIN<\/code> \u548c <code>MAX<\/code>\u3002\u9019\u4e9b\u51fd\u6578\u53ef\u4ee5\u5e6b\u52a9\u7528\u6236\u5feb\u901f\u7372\u53d6\u7d71\u8a08\u4fe1\u606f\u3002<\/p>\n<h3 id=\"count-%e5%87%bd%e6%95%b8-yjRCaAIbEA\">COUNT \u51fd\u6578<\/h3>\n<p><code>COUNT<\/code> \u51fd\u6578\u7528\u65bc\u8a08\u7b97\u8868\u4e2d\u7b26\u5408\u689d\u4ef6\u7684\u8a18\u9304\u6578\u91cf\u3002\u4ee5\u4e0b\u662f\u5176\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>SELECT COUNT(*)\nFROM \u8868\u540d\nWHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u8a08\u7b97 <code>employees<\/code> \u8868\u4e2d\u6240\u6709\u54e1\u5de5\u7684\u6578\u91cf\uff1a<\/p>\n<pre><code>SELECT COUNT(*)\nFROM employees;<\/code><\/pre>\n<h3 id=\"sum-%e5%87%bd%e6%95%b8-yjRCaAIbEA\">SUM \u51fd\u6578<\/h3>\n<p><code>SUM<\/code> \u51fd\u6578\u7528\u65bc\u8a08\u7b97\u67d0\u500b\u6578\u503c\u6b04\u4f4d\u7684\u7e3d\u548c\u3002\u4ee5\u4e0b\u662f\u5176\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>SELECT SUM(\u6b04\u4f4d\u540d)\nFROM \u8868\u540d\nWHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u8a08\u7b97\u6240\u6709\u54e1\u5de5\u7684\u85aa\u6c34\u7e3d\u548c\uff1a<\/p>\n<pre><code>SELECT SUM(salary)\nFROM employees;<\/code><\/pre>\n<h3 id=\"avg-%e5%87%bd%e6%95%b8-yjRCaAIbEA\">AVG \u51fd\u6578<\/h3>\n<p><code>AVG<\/code> \u51fd\u6578\u7528\u65bc\u8a08\u7b97\u67d0\u500b\u6578\u503c\u6b04\u4f4d\u7684\u5e73\u5747\u503c\u3002\u4ee5\u4e0b\u662f\u5176\u57fa\u672c\u8a9e\u6cd5\uff1a<\/p>\n<pre><code>SELECT AVG(\u6b04\u4f4d\u540d)\nFROM \u8868\u540d\nWHERE \u689d\u4ef6;<\/code><\/pre>\n<p>\u4f8b\u5982\uff0c\u8a08\u7b97\u6240\u6709\u54e1\u5de5\u7684\u5e73\u5747\u85aa\u6c34\uff1a<\/p>\n<pre><code>SELECT AVG(salary)\nFROM employees;<\/code><\/pre>\n<h2 id=\"%e7%b5%90%e8%ab%96-yjRCaAIbEA\">\u7d50\u8ad6<\/h2>\n<p>\u5728\u9019\u7bc7\u6587\u7ae0\u4e2d\uff0c\u6211\u5011\u63a2\u8a0e\u4e86 SQL \u8a9e\u8a00\u4e2d\u7684\u8cc7\u6599\u66f4\u65b0\u3001\u522a\u9664\u4ee5\u53ca\u805a\u5408\u51fd\u6578\u7684\u4f7f\u7528\u3002\u9019\u4e9b\u529f\u80fd\u662f\u9032\u884c\u6578\u64da\u7ba1\u7406\u548c\u5206\u6790\u7684\u57fa\u790e\uff0c\u638c\u63e1\u5b83\u5011\u5c07\u6709\u52a9\u65bc\u63d0\u9ad8\u60a8\u7684\u6578\u64da\u8655\u7406\u80fd\u529b\u3002\u96a8\u8457\u5c0d SQL \u8a9e\u8a00\u7684\u6df1\u5165\u4e86\u89e3\uff0c\u60a8\u5c07\u80fd\u5920\u66f4\u6709\u6548\u5730\u7ba1\u7406\u548c\u5206\u6790\u6578\u64da\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc\u4f7f\u7528 <a href=\"https:\/\/server.hk\">VPS<\/a> \u9032\u884c\u6578\u64da\u5eab\u7ba1\u7406\u6709\u8208\u8da3\uff0c\u6216\u60f3\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u7684\u8cc7\u8a0a\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8cc7\u6e90\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u638c\u63e1 SQL \u8a9e\u8a00\u7684\u9032\u968e\u6280\u5de7\uff0c\u5feb\u901f\u5b78\u7fd2\u67e5\u8a62\u3001\u6578\u64da\u64cd\u4f5c\u53ca\u6700\u4f73\u5be6\u8e10\uff0c\u63d0\u5347\u6578\u64da\u7ba1\u7406\u80fd\u529b\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-168477","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168477","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=168477"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168477\/revisions"}],"predecessor-version":[{"id":168478,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/168477\/revisions\/168478"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=168477"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=168477"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=168477"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}