{"id":60507,"date":"2024-10-13T03:26:21","date_gmt":"2024-10-12T19:26:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/60507\/"},"modified":"2024-10-13T03:26:21","modified_gmt":"2024-10-12T19:26:21","slug":"db2%e5%85%ac%e5%85%b1%e8%a1%a8%e8%a1%a8%e9%81%94%e5%bc%8f%e7%9a%84%e7%94%a8%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/60507\/","title":{"rendered":"DB2\u516c\u5171\u8868\u8868\u9054\u5f0f\u7684\u7528\u6cd5"},"content":{"rendered":"<h1 id=\"db2%e5%85%ac%e5%85%b1%e8%a1%a8%e8%a1%a8%e9%81%94%e5%bc%8f%e7%9a%84%e7%94%a8%e6%b3%95-bglrhdQBvW\">DB2\u516c\u5171\u8868\u8868\u9054\u5f0f\u7684\u7528\u6cd5<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cIBM\u7684DB2\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u5ee3\u6cdb\u61c9\u7528\u65bc\u4f01\u696d\u7d1a\u61c9\u7528\u7a0b\u5e8f\u4e2d\u3002DB2\u7684\u516c\u5171\u8868\u8868\u9054\u5f0f\uff08Common Table Expressions\uff0cCTE\uff09\u662f\u4e00\u7a2e\u5f37\u5927\u7684\u67e5\u8a62\u529f\u80fd\uff0c\u80fd\u5920\u7c21\u5316\u8907\u96dc\u67e5\u8a62\u7684\u7de8\u5beb\u548c\u7406\u89e3\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eDB2\u516c\u5171\u8868\u8868\u9054\u5f0f\u7684\u7528\u6cd5\u53ca\u5176\u512a\u52e2\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af%e5%85%ac%e5%85%b1%e8%a1%a8%e8%a1%a8%e9%81%94%e5%bc%8f%ef%bc%88cte%ef%bc%89%ef%bc%9f-bglrhdQBvW\">\u4ec0\u9ebc\u662f\u516c\u5171\u8868\u8868\u9054\u5f0f\uff08CTE\uff09\uff1f<\/h2>\n<p>\u516c\u5171\u8868\u8868\u9054\u5f0f\u662f\u4e00\u7a2e\u81e8\u6642\u7d50\u679c\u96c6\uff0c\u53ef\u4ee5\u5728\u4e00\u500b\u67e5\u8a62\u4e2d\u591a\u6b21\u5f15\u7528\u3002CTE\u7684\u8a9e\u6cd5\u901a\u5e38\u4ee5WITH\u95dc\u9375\u5b57\u958b\u59cb\uff0c\u5f8c\u63a5\u4e00\u500b\u6216\u591a\u500bCTE\u5b9a\u7fa9\uff0c\u7136\u5f8c\u662f\u4e3b\u67e5\u8a62\u3002CTE\u7684\u4e3b\u8981\u512a\u52e2\u5728\u65bc\u63d0\u9ad8\u67e5\u8a62\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u8907\u96dc\u7684\u67e5\u8a62\u6642\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-bglrhdQBvW\">CTE\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<pre><code>WITH cte_name AS (\n    SELECT column1, column2\n    FROM table_name\n    WHERE condition\n)\nSELECT *\nFROM cte_name;\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u9996\u5148\u5b9a\u7fa9\u4e86\u4e00\u500b\u540d\u70ba<code>cte_name<\/code>\u7684CTE\uff0c\u7136\u5f8c\u5728\u4e3b\u67e5\u8a62\u4e2d\u5f15\u7528\u5b83\u3002\u9019\u6a23\u7684\u7d50\u69cb\u4f7f\u5f97\u67e5\u8a62\u66f4\u52a0\u6e05\u6670\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e4%bd%bf%e7%94%a8%e5%a0%b4%e6%99%af-bglrhdQBvW\">CTE\u7684\u4f7f\u7528\u5834\u666f<\/h2>\n<h3 id=\"1-%e7%b0%a1%e5%8c%96%e8%a4%87%e9%9b%9c%e6%9f%a5%e8%a9%a2-bglrhdQBvW\">1. \u7c21\u5316\u8907\u96dc\u67e5\u8a62<\/h3>\n<p>\u7576\u67e5\u8a62\u6d89\u53ca\u591a\u500b\u5b50\u67e5\u8a62\u6642\uff0c\u4f7f\u7528CTE\u53ef\u4ee5\u5c07\u9019\u4e9b\u5b50\u67e5\u8a62\u63d0\u53d6\u51fa\u4f86\uff0c\u5f9e\u800c\u4f7f\u4e3b\u67e5\u8a62\u66f4\u52a0\u7c21\u6f54\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>WITH SalesCTE AS (\n    SELECT SalesPersonID, SUM(TotalAmount) AS TotalSales\n    FROM Sales\n    GROUP BY SalesPersonID\n)\nSELECT sp.Name, s.TotalSales\nFROM SalesCTE s\nJOIN SalesPerson sp ON s.SalesPersonID = sp.ID;\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u9996\u5148\u8a08\u7b97\u6bcf\u4f4d\u92b7\u552e\u4eba\u54e1\u7684\u7e3d\u92b7\u552e\u984d\uff0c\u7136\u5f8c\u5728\u4e3b\u67e5\u8a62\u4e2d\u5f15\u7528\u9019\u500b\u7d50\u679c\u96c6\u3002<\/p>\n<h3 id=\"2-%e9%81%9e%e6%ad%b8%e6%9f%a5%e8%a9%a2-bglrhdQBvW\">2. \u905e\u6b78\u67e5\u8a62<\/h3>\n<p>CTE\u9084\u652f\u6301\u905e\u6b78\u67e5\u8a62\uff0c\u9019\u5c0d\u65bc\u8655\u7406\u5c64\u6b21\u7d50\u69cb\u6578\u64da\uff08\u5982\u7d44\u7e54\u7d50\u69cb\u6216\u7522\u54c1\u5206\u985e\uff09\u975e\u5e38\u6709\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u905e\u6b78CTE\u7684\u4f8b\u5b50\uff1a<\/p>\n<pre><code>WITH RECURSIVE EmployeeCTE AS (\n    SELECT EmployeeID, ManagerID, Name\n    FROM Employees\n    WHERE ManagerID IS NULL\n    UNION ALL\n    SELECT e.EmployeeID, e.ManagerID, e.Name\n    FROM Employees e\n    INNER JOIN EmployeeCTE ec ON e.ManagerID = ec.EmployeeID\n)\nSELECT * FROM EmployeeCTE;\n<\/code><\/pre>\n<p>\u9019\u6bb5\u4ee3\u78bc\u5c07\u8fd4\u56de\u6240\u6709\u54e1\u5de5\u53ca\u5176\u7ba1\u7406\u8005\u7684\u5c64\u6b21\u7d50\u69cb\u3002<\/p>\n<h2 id=\"cte%e7%9a%84%e5%84%aa%e5%8b%a2-bglrhdQBvW\">CTE\u7684\u512a\u52e2<\/h2>\n<ul>\n<li><strong>\u53ef\u8b80\u6027\uff1a<\/strong>CTE\u4f7f\u5f97\u67e5\u8a62\u7d50\u69cb\u66f4\u52a0\u6e05\u6670\uff0c\u6613\u65bc\u7406\u89e3\u3002<\/li>\n<li><strong>\u91cd\u7528\u6027\uff1a<\/strong>CTE\u53ef\u4ee5\u5728\u540c\u4e00\u67e5\u8a62\u4e2d\u591a\u6b21\u5f15\u7528\uff0c\u907f\u514d\u91cd\u8907\u4ee3\u78bc\u3002<\/li>\n<li><strong>\u905e\u6b78\u80fd\u529b\uff1a<\/strong>CTE\u652f\u6301\u905e\u6b78\u67e5\u8a62\uff0c\u9069\u5408\u8655\u7406\u5c64\u6b21\u7d50\u69cb\u6578\u64da\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-bglrhdQBvW\">\u7e3d\u7d50<\/h2>\n<p>DB2\u7684\u516c\u5171\u8868\u8868\u9054\u5f0f\uff08CTE\uff09\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u7c21\u5316\u8907\u96dc\u67e5\u8a62\uff0c\u63d0\u9ad8\u67e5\u8a62\u7684\u53ef\u8b80\u6027\u548c\u53ef\u7dad\u8b77\u6027\u3002\u7121\u8ad6\u662f\u7c21\u5316\u67e5\u8a62\u9084\u662f\u8655\u7406\u5c64\u6b21\u7d50\u69cb\u6578\u64da\uff0cCTE\u90fd\u80fd\u63d0\u4f9b\u6709\u6548\u7684\u89e3\u6c7a\u65b9\u6848\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\u4f86\u8aaa\uff0c\u638c\u63e1CTE\u7684\u7528\u6cd5\u5c07\u5927\u5927\u63d0\u5347\u6578\u64da\u67e5\u8a62\u7684\u6548\u7387\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u8655\u7406\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u4f86\u652f\u6301\u60a8\u7684DB2\u6578\u64da\u5eab\u61c9\u7528\uff0c\u63d0\u4f9b\u7a69\u5b9a\u7684\u6027\u80fd\u548c\u9748\u6d3b\u7684\u64f4\u5c55\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22DB2\u516c\u5171\u8868\u8868\u9054\u5f0f\u7684\u7528\u6cd5\uff0c\u4e86\u89e3\u5982\u4f55\u7c21\u5316\u67e5\u8a62\u3001\u63d0\u9ad8\u53ef\u8b80\u6027\u53ca\u91cd\u7528SQL\u4ee3\u78bc\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-60507","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60507","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=60507"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60507\/revisions"}],"predecessor-version":[{"id":60508,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/60507\/revisions\/60508"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=60507"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=60507"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=60507"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}