{"id":139376,"date":"2024-10-31T18:33:23","date_gmt":"2024-10-31T10:33:23","guid":{"rendered":"https:\/\/server.hk\/cnblog\/139376\/"},"modified":"2024-10-31T18:33:24","modified_gmt":"2024-10-31T10:33:24","slug":"sql-server%e6%95%b8%e6%93%9a%e5%ba%ab%e5%a4%9a%e7%a8%ae%e6%96%b9%e5%bc%8f%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/139376\/","title":{"rendered":"SQL Server\u6578\u64da\u5eab\u591a\u7a2e\u65b9\u5f0f\u67e5\u627e\u91cd\u8907\u8a18\u9304"},"content":{"rendered":"<h1 id=\"sql-server%e6%95%b8%e6%93%9a%e5%ba%ab%e5%a4%9a%e7%a8%ae%e6%96%b9%e5%bc%8f%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-RIRpKfzOIM\">SQL Server\u6578\u64da\u5eab\u591a\u7a2e\u65b9\u5f0f\u67e5\u627e\u91cd\u8907\u8a18\u9304<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u91cd\u8907\u8a18\u9304\u7684\u5b58\u5728\u53ef\u80fd\u6703\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\u6027\uff0c\u5f71\u97ff\u67e5\u8a62\u7d50\u679c\u7684\u6e96\u78ba\u6027\u3002\u56e0\u6b64\uff0c\u8b58\u5225\u548c\u8655\u7406\u91cd\u8907\u8a18\u9304\u662f\u6578\u64da\u5eab\u7ba1\u7406\u7684\u91cd\u8981\u4efb\u52d9\u4e4b\u4e00\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5728SQL Server\u4e2d\u67e5\u627e\u91cd\u8907\u8a18\u9304\u7684\u591a\u7a2e\u65b9\u6cd5\uff0c\u5e6b\u52a9\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u6709\u6548\u5730\u7ba1\u7406\u6578\u64da\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8group-by%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-RIRpKfzOIM\">\u4f7f\u7528GROUP BY\u67e5\u627e\u91cd\u8907\u8a18\u9304<\/h2>\n<p>\u6700\u5e38\u898b\u7684\u65b9\u6cd5\u4e4b\u4e00\u662f\u4f7f\u7528<code>GROUP BY<\/code>\u8a9e\u53e5\u3002\u9019\u7a2e\u65b9\u6cd5\u53ef\u4ee5\u5c07\u6578\u64da\u5206\u7d44\uff0c\u4e26\u4f7f\u7528\u805a\u5408\u51fd\u6578\u4f86\u8a08\u7b97\u6bcf\u7d44\u7684\u8a18\u9304\u6578\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>Customers<\/code>\u7684\u8868\uff0c\u4e26\u5e0c\u671b\u67e5\u627e\u91cd\u8907\u7684\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\uff1a<\/p>\n<pre><code>SELECT Email, COUNT(*) AS Count\nFROM Customers\nGROUP BY Email\nHAVING COUNT(*) &gt; 1;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6211\u5011\u9078\u64c7\u4e86<code>Email<\/code>\u6b04\u4f4d\uff0c\u4e26\u8a08\u7b97\u6bcf\u500b\u96fb\u5b50\u90f5\u4ef6\u7684\u51fa\u73fe\u6b21\u6578\u3002<code>HAVING<\/code>\u5b50\u53e5\u7528\u65bc\u904e\u6ffe\u51fa\u51fa\u73fe\u6b21\u6578\u5927\u65bc1\u7684\u96fb\u5b50\u90f5\u4ef6\uff0c\u5f9e\u800c\u627e\u51fa\u91cd\u8907\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8cte%ef%bc%88%e5%85%ac%e7%94%a8%e8%a1%a8%e8%a1%a8%e9%81%94%e5%bc%8f%ef%bc%89%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-RIRpKfzOIM\">\u4f7f\u7528CTE\uff08\u516c\u7528\u8868\u8868\u9054\u5f0f\uff09\u67e5\u627e\u91cd\u8907\u8a18\u9304<\/h2>\n<p>\u53e6\u4e00\u7a2e\u65b9\u6cd5\u662f\u4f7f\u7528\u516c\u7528\u8868\u8868\u9054\u5f0f\uff08CTE\uff09\u3002CTE\u53ef\u4ee5\u4f7f\u67e5\u8a62\u66f4\u5177\u53ef\u8b80\u6027\uff0c\u4e26\u4e14\u5728\u8655\u7406\u8907\u96dc\u67e5\u8a62\u6642\u975e\u5e38\u6709\u7528\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528CTE\u67e5\u627e\u91cd\u8907\u8a18\u9304\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>WITH DuplicateEmails AS (\n    SELECT Email, COUNT(*) AS Count\n    FROM Customers\n    GROUP BY Email\n    HAVING COUNT(*) &gt; 1\n)\nSELECT * FROM DuplicateEmails;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u793a\u4f8b\u4e2d\uff0c\u6211\u5011\u9996\u5148\u5b9a\u7fa9\u4e86\u4e00\u500bCTE\uff0c\u7136\u5f8c\u5f9e\u4e2d\u9078\u64c7\u6240\u6709\u91cd\u8907\u7684\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u53ca\u5176\u8a08\u6578\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8row_number%e5%87%bd%e6%95%b8%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-RIRpKfzOIM\">\u4f7f\u7528ROW_NUMBER()\u51fd\u6578\u67e5\u627e\u91cd\u8907\u8a18\u9304<\/h2>\n<p>\u4f7f\u7528<code>ROW_NUMBER()<\/code>\u51fd\u6578\u4e5f\u662f\u4e00\u7a2e\u6709\u6548\u7684\u65b9\u6cd5\u3002\u9019\u500b\u51fd\u6578\u53ef\u4ee5\u70ba\u6bcf\u4e00\u884c\u5206\u914d\u4e00\u500b\u552f\u4e00\u7684\u5e8f\u865f\uff0c\u7136\u5f8c\u6211\u5011\u53ef\u4ee5\u6839\u64da\u9019\u500b\u5e8f\u865f\u4f86\u8b58\u5225\u91cd\u8907\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n<pre><code>WITH NumberedEmails AS (\n    SELECT Email, ROW_NUMBER() OVER (PARTITION BY Email ORDER BY (SELECT NULL)) AS RowNum\n    FROM Customers\n)\nSELECT Email\nFROM NumberedEmails\nWHERE RowNum &gt; 1;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6211\u5011\u4f7f\u7528<code>PARTITION BY<\/code>\u4f86\u6839\u64da\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\u5206\u7d44\uff0c\u4e26\u70ba\u6bcf\u7d44\u4e2d\u7684\u6bcf\u4e00\u884c\u5206\u914d\u4e00\u500b\u5e8f\u865f\u3002\u7136\u5f8c\uff0c\u6211\u5011\u9078\u64c7\u5e8f\u865f\u5927\u65bc1\u7684\u96fb\u5b50\u90f5\u4ef6\uff0c\u9019\u6a23\u5c31\u80fd\u627e\u51fa\u6240\u6709\u91cd\u8907\u7684\u8a18\u9304\u3002<\/p>\n<h2 id=\"%e4%bd%bf%e7%94%a8distinct%e5%92%8cexists%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84-RIRpKfzOIM\">\u4f7f\u7528DISTINCT\u548cEXISTS\u67e5\u627e\u91cd\u8907\u8a18\u9304<\/h2>\n<p>\u6700\u5f8c\uff0c\u6211\u5011\u9084\u53ef\u4ee5\u4f7f\u7528<code>DISTINCT<\/code>\u548c<code>EXISTS<\/code>\u4f86\u67e5\u627e\u91cd\u8907\u8a18\u9304\u3002\u9019\u7a2e\u65b9\u6cd5\u76f8\u5c0d\u8f03\u5c11\u4f7f\u7528\uff0c\u4f46\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u4e5f\u975e\u5e38\u6709\u6548\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT DISTINCT a.Email\nFROM Customers a\nWHERE EXISTS (\n    SELECT 1\n    FROM Customers b\n    WHERE a.Email = b.Email\n    GROUP BY b.Email\n    HAVING COUNT(*) &gt; 1\n);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u6211\u5011\u9078\u64c7\u4e86\u6240\u6709\u4e0d\u540c\u7684\u96fb\u5b50\u90f5\u4ef6\u5730\u5740\uff0c\u4e26\u4f7f\u7528<code>EXISTS<\/code>\u4f86\u6aa2\u67e5\u662f\u5426\u5b58\u5728\u91cd\u8907\u7684\u96fb\u5b50\u90f5\u4ef6\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-RIRpKfzOIM\">\u7e3d\u7d50<\/h2>\n<p>\u5728SQL Server\u4e2d\uff0c\u6709\u591a\u7a2e\u65b9\u6cd5\u53ef\u4ee5\u67e5\u627e\u91cd\u8907\u8a18\u9304\uff0c\u5305\u62ec\u4f7f\u7528<code>GROUP BY<\/code>\u3001CTE\u3001<code>ROW_NUMBER()<\/code>\u51fd\u6578\u4ee5\u53ca<code>DISTINCT<\/code>\u548c<code>EXISTS<\/code>\u3002\u9078\u64c7\u5408\u9069\u7684\u65b9\u6cd5\u53d6\u6c7a\u65bc\u5177\u9ad4\u7684\u9700\u6c42\u548c\u6578\u64da\u7d50\u69cb\u3002\u6709\u6548\u5730\u7ba1\u7406\u91cd\u8907\u8a18\u9304\u4e0d\u50c5\u80fd\u63d0\u9ad8\u6578\u64da\u7684\u6e96\u78ba\u6027\uff0c\u9084\u80fd\u589e\u5f37\u6578\u64da\u5eab\u7684\u6574\u9ad4\u6027\u80fd\u3002<\/p>\n<p>\u5982\u679c\u60a8\u9700\u8981\u66f4\u591a\u6709\u95dc\u6578\u64da\u5eab\u7ba1\u7406\u7684\u8cc7\u8a0a\uff0c\u6216\u662f\u5c0b\u627e\u9ad8\u6548\u7684<code><a href=\"https:\/\/server.hk\">VPS<\/a><\/code>\u89e3\u6c7a\u65b9\u6848\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8a73\u7d30\u8cc7\u6599\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u591a\u7a2e\u65b9\u6cd5\u5728SQL Server\u6578\u64da\u5eab\u4e2d\u67e5\u627e\u91cd\u8907\u8a18\u9304\uff0c\u63d0\u5347\u6578\u64da\u7ba1\u7406\u6548\u7387\uff0c\u78ba\u4fdd\u6578\u64da\u6e96\u78ba\u6027\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-139376","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/139376","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=139376"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/139376\/revisions"}],"predecessor-version":[{"id":139377,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/139376\/revisions\/139377"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=139376"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=139376"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=139376"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}