{"id":174717,"date":"2024-11-07T23:09:24","date_gmt":"2024-11-07T15:09:24","guid":{"rendered":"https:\/\/server.hk\/cnblog\/174717\/"},"modified":"2024-11-07T23:09:25","modified_gmt":"2024-11-07T15:09:25","slug":"%e5%a6%82%e4%bd%95%e5%bf%ab%e9%80%9f%e4%b8%8a%e6%89%8bsql-cte","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/174717\/","title":{"rendered":"\u5982\u4f55\u5feb\u901f\u4e0a\u624bSQL CTE?"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e5%bf%ab%e9%80%9f%e4%b8%8a%e6%89%8bsql-cte-sNGTfXcIdf\">\u5982\u4f55\u5feb\u901f\u4e0a\u624bSQL CTE?<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u548c\u67e5\u8a62\u4e2d\uff0cSQL\uff08\u7d50\u69cb\u5316\u67e5\u8a62\u8a9e\u8a00\uff09\u662f\u4e00\u500b\u4e0d\u53ef\u6216\u7f3a\u7684\u5de5\u5177\u3002\u96a8\u8457\u6578\u64da\u91cf\u7684\u589e\u52a0\uff0c\u67e5\u8a62\u7684\u8907\u96dc\u6027\u4e5f\u96a8\u4e4b\u4e0a\u5347\u3002\u70ba\u4e86\u7c21\u5316\u67e5\u8a62\uff0cSQL\u63d0\u4f9b\u4e86\u4e00\u7a2e\u540d\u70baCTE\uff08\u516c\u7528\u8868\u9054\u5f0f\uff0cCommon Table Expression\uff09\u7684\u529f\u80fd\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5982\u4f55\u5feb\u901f\u4e0a\u624bSQL CTE\uff0c\u4e26\u63d0\u4f9b\u5be6\u7528\u7684\u7bc4\u4f8b\u548c\u6280\u5de7\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%afcte-sNGTfXcIdf\">\u4ec0\u9ebc\u662fCTE?<\/h2>\n<p>CTE\u662f\u4e00\u7a2e\u81e8\u6642\u7d50\u679c\u96c6\uff0c\u53ef\u4ee5\u5728\u4e00\u500b\u67e5\u8a62\u4e2d\u591a\u6b21\u5f15\u7528\u3002\u5b83\u7684\u4e3b\u8981\u512a\u52e2\u5728\u65bc\u63d0\u9ad8\u67e5\u8a62\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\u3002CTE\u901a\u5e38\u7528\u65bc\u7c21\u5316\u8907\u96dc\u7684\u67e5\u8a62\uff0c\u7279\u5225\u662f\u5728\u9700\u8981\u591a\u6b21\u4f7f\u7528\u76f8\u540c\u5b50\u67e5\u8a62\u7684\u60c5\u6cc1\u4e0b\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-sNGTfXcIdf\">CTE\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>CTE\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>WITH CTE_Name AS (\n    -- \u67e5\u8a62\u8a9e\u53e5\n    SELECT column1, column2\n    FROM table_name\n    WHERE condition\n)\nSELECT *\nFROM CTE_Name;<\/code><\/pre>\n<p>\u5728\u9019\u6bb5\u8a9e\u6cd5\u4e2d\uff0c<code>WITH<\/code>\u95dc\u9375\u5b57\u7528\u65bc\u5b9a\u7fa9CTE\uff0c<code>CTE_Name<\/code>\u662fCTE\u7684\u540d\u7a31\uff0c\u5f8c\u9762\u8ddf\u96a8\u7684\u67e5\u8a62\u8a9e\u53e5\u5247\u662fCTE\u7684\u5167\u5bb9\u3002\u6700\u5f8c\uff0c\u6211\u5011\u53ef\u4ee5\u5728\u4e3b\u67e5\u8a62\u4e2d\u5f15\u7528\u9019\u500bCTE\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e4%bd%bf%e7%94%a8%e7%af%84%e4%be%8b-sNGTfXcIdf\">CTE\u7684\u4f7f\u7528\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528CTE\u7684\u7bc4\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>employees<\/code>\u7684\u8868\u683c\uff0c\u5305\u542b\u54e1\u5de5\u7684ID\u3001\u59d3\u540d\u548c\u85aa\u6c34\u3002\u6211\u5011\u5e0c\u671b\u627e\u51fa\u85aa\u6c34\u9ad8\u65bc50000\u7684\u54e1\u5de5\u3002<\/p>\n<pre><code>WITH HighSalaryEmployees AS (\n    SELECT id, name, salary\n    FROM employees\n    WHERE salary &gt; 50000\n)\nSELECT *\nFROM HighSalaryEmployees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u9996\u5148\u5b9a\u7fa9\u4e86\u4e00\u500b\u540d\u70ba<code>HighSalaryEmployees<\/code>\u7684CTE\uff0c\u7136\u5f8c\u5728\u4e3b\u67e5\u8a62\u4e2d\u5f15\u7528\u5b83\u3002\u9019\u6a23\u7684\u505a\u6cd5\u4f7f\u5f97\u67e5\u8a62\u7d50\u69cb\u66f4\u52a0\u6e05\u6670\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e9%81%9e%e8%bf%b4%e6%9f%a5%e8%a9%a2-sNGTfXcIdf\">CTE\u7684\u905e\u8ff4\u67e5\u8a62<\/h2>\n<p>CTE\u9084\u652f\u6301\u905e\u8ff4\u67e5\u8a62\uff0c\u9019\u5c0d\u65bc\u8655\u7406\u5c64\u6b21\u7d50\u69cb\u6578\u64da\uff08\u5982\u7d44\u7e54\u7d50\u69cb\u6216\u76ee\u9304\u7d50\u69cb\uff09\u975e\u5e38\u6709\u7528\u3002\u905e\u8ff4CTE\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>WITH RECURSIVE CTE_Name AS (\n    -- \u57fa\u672c\u67e5\u8a62\n    SELECT column1, column2\n    FROM table_name\n    WHERE condition\n    UNION ALL\n    -- \u905e\u8ff4\u67e5\u8a62\n    SELECT column1, column2\n    FROM table_name\n    JOIN CTE_Name ON table_name.column = CTE_Name.column\n)\nSELECT *\nFROM CTE_Name;<\/code><\/pre>\n<p>\u5728\u9019\u6bb5\u8a9e\u6cd5\u4e2d\uff0c<code>UNION ALL<\/code>\u7528\u65bc\u5c07\u57fa\u672c\u67e5\u8a62\u548c\u905e\u8ff4\u67e5\u8a62\u7684\u7d50\u679c\u5408\u4f75\u3002\u9019\u6a23\u53ef\u4ee5\u4e0d\u65b7\u5730\u5f9eCTE\u4e2d\u63d0\u53d6\u6578\u64da\uff0c\u76f4\u5230\u6eff\u8db3\u7279\u5b9a\u689d\u4ef6\u70ba\u6b62\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e5%84%aa%e5%8b%a2-sNGTfXcIdf\">CTE\u7684\u512a\u52e2<\/h2>\n<ul>\n<li><strong>\u63d0\u9ad8\u53ef\u8b80\u6027\uff1a<\/strong>CTE\u4f7f\u5f97\u8907\u96dc\u67e5\u8a62\u7684\u7d50\u69cb\u66f4\u52a0\u6e05\u6670\uff0c\u6613\u65bc\u7406\u89e3\u3002<\/li>\n<li><strong>\u91cd\u7528\u67e5\u8a62\uff1a<\/strong>\u53ef\u4ee5\u5728\u540c\u4e00\u67e5\u8a62\u4e2d\u591a\u6b21\u5f15\u7528CTE\uff0c\u907f\u514d\u91cd\u8907\u4ee3\u78bc\u3002<\/li>\n<li><strong>\u652f\u6301\u905e\u8ff4\uff1a<\/strong>\u80fd\u5920\u8655\u7406\u5c64\u6b21\u7d50\u69cb\u6578\u64da\uff0c\u63d0\u4f9b\u9748\u6d3b\u7684\u67e5\u8a62\u65b9\u5f0f\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-sNGTfXcIdf\">\u7e3d\u7d50<\/h2>\n<p>CTE\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u7c21\u5316SQL\u67e5\u8a62\uff0c\u63d0\u9ad8\u4ee3\u78bc\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\u3002\u7121\u8ad6\u662f\u57fa\u672c\u67e5\u8a62\u9084\u662f\u905e\u8ff4\u67e5\u8a62\uff0cCTE\u90fd\u80fd\u63d0\u4f9b\u9748\u6d3b\u7684\u89e3\u6c7a\u65b9\u6848\u3002\u5c0d\u65bc\u9700\u8981\u8655\u7406\u8907\u96dc\u6578\u64da\u7684\u958b\u767c\u8005\u4f86\u8aaa\uff0c\u638c\u63e1CTE\u7684\u4f7f\u7528\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u4f86\u652f\u6301\u60a8\u7684\u61c9\u7528\u7a0b\u5e8f\u548c\u6578\u64da\u7ba1\u7406\u9700\u6c42\u3002\u7121\u8ad6\u662f<a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a>\u9084\u662f<a href=\"https:\/\/server.hk\">\u96f2\u4f3a\u670d\u5668<\/a>\uff0cServer.HK\u90fd\u80fd\u63d0\u4f9b\u7a69\u5b9a\u7684\u6027\u80fd\u548c\u53ef\u9760\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5feb\u901f\u638c\u63e1SQL CTE\u7684\u6280\u5de7\u4e0e\u793a\u4f8b\uff0c\u8f7b\u677e\u63d0\u5347\u67e5\u8be2\u6548\u7387\uff0c\u52a9\u4f60\u5728\u6570\u636e\u5904\u7406\u4e0a\u6e38\u5203\u6709\u4f59\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-174717","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/174717","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=174717"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/174717\/revisions"}],"predecessor-version":[{"id":174718,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/174717\/revisions\/174718"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=174717"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=174717"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=174717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}