{"id":175201,"date":"2024-11-08T03:53:33","date_gmt":"2024-11-07T19:53:33","guid":{"rendered":"https:\/\/server.hk\/cnblog\/175201\/"},"modified":"2024-11-08T03:53:34","modified_gmt":"2024-11-07T19:53:34","slug":"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8db2%e6%9f%a5%e6%89%be%e9%87%8d%e8%a4%87%e6%95%b8%e6%93%9a%e5%ba%ab%e6%95%b8%e6%93%9a%ef%bc%9f-db2%e6%9f%a5%e9%87%8d%e8%a4%87%e6%95%b8%e6%93%9a%e5%ba%ab","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/175201\/","title":{"rendered":"\u5982\u4f55\u4f7f\u7528DB2\u67e5\u627e\u91cd\u8907\u6578\u64da\u5eab\u6578\u64da\uff1f (db2\u67e5\u91cd\u8907\u6578\u64da\u5eab)"},"content":{"rendered":"

\u5982\u4f55\u4f7f\u7528DB2\u67e5\u627e\u91cd\u8907\u6578\u64da\u5eab\u6578\u64da\uff1f<\/h1>\n

\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u91cd\u8907\u6578\u64da\u662f\u4e00\u500b\u5e38\u898b\u7684\u554f\u984c\uff0c\u7279\u5225\u662f\u5728\u5927\u578b\u6578\u64da\u5eab\u4e2d\u3002IBM\u7684DB2\u6578\u64da\u5eab\u7cfb\u7d71\u63d0\u4f9b\u4e86\u591a\u7a2e\u5de5\u5177\u548c\u67e5\u8a62\u8a9e\u8a00\uff0c\u5e6b\u52a9\u7528\u6236\u8b58\u5225\u548c\u8655\u7406\u91cd\u8907\u6578\u64da\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5982\u4f55\u4f7f\u7528DB2\u67e5\u627e\u91cd\u8907\u6578\u64da\u5eab\u6578\u64da\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u5be6\u7528\u7684\u793a\u4f8b\u548c\u4ee3\u78bc\u7247\u6bb5\u3002<\/p>\n

\u91cd\u8907\u6578\u64da\u7684\u5b9a\u7fa9<\/h2>\n

\u91cd\u8907\u6578\u64da\u662f\u6307\u5728\u6578\u64da\u5eab\u4e2d\u51fa\u73fe\u591a\u6b21\u7684\u76f8\u540c\u6578\u64da\u689d\u76ee\u3002\u9019\u53ef\u80fd\u6703\u5c0e\u81f4\u6578\u64da\u4e0d\u4e00\u81f4\u6027\uff0c\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u4e26\u589e\u52a0\u5b58\u5132\u6210\u672c\u3002\u56e0\u6b64\uff0c\u5b9a\u671f\u6aa2\u67e5\u548c\u6e05\u7406\u91cd\u8907\u6578\u64da\u662f\u6578\u64da\u5eab\u7ba1\u7406\u7684\u91cd\u8981\u4efb\u52d9\u3002<\/p>\n

\u4f7f\u7528DB2\u67e5\u627e\u91cd\u8907\u6578\u64da\u7684\u57fa\u672c\u65b9\u6cd5<\/h2>\n

\u5728DB2\u4e2d\uff0c\u67e5\u627e\u91cd\u8907\u6578\u64da\u901a\u5e38\u4f7f\u7528SQL\u67e5\u8a62\u4f86\u5be6\u73fe\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u7684\u65b9\u6cd5\uff1a<\/p>\n

1. \u4f7f\u7528GROUP BY\u548cHAVING\u5b50\u53e5<\/h3>\n

\u6700\u5e38\u898b\u7684\u65b9\u6cd5\u662f\u4f7f\u7528GROUP BY\u5b50\u53e5\u4f86\u5206\u7d44\u6578\u64da\uff0c\u7136\u5f8c\u4f7f\u7528HAVING\u5b50\u53e5\u4f86\u7be9\u9078\u51fa\u91cd\u8907\u7684\u689d\u76ee\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n

SELECT column_name, COUNT(*)\nFROM table_name\nGROUP BY column_name\nHAVING COUNT(*) > 1;<\/code><\/pre>\n
\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0ccolumn_name<\/code>\u662f\u4f60\u60f3\u8981\u6aa2\u67e5\u91cd\u8907\u7684\u5217\u540d\uff0ctable_name<\/code>\u662f\u4f60\u7684\u6578\u64da\u8868\u540d\u3002\u9019\u500b\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u91cd\u8907\u7684\u6578\u64da\u689d\u76ee\u53ca\u5176\u51fa\u73fe\u7684\u6b21\u6578\u3002<\/p>\n
2. \u4f7f\u7528CTE\uff08\u516c\u7528\u8868\u8868\u9054\u5f0f\uff09<\/h3>\n
\u53e6\u4e00\u7a2e\u65b9\u6cd5\u662f\u4f7f\u7528\u516c\u7528\u8868\u8868\u9054\u5f0f\uff08CTE\uff09\u4f86\u67e5\u627e\u91cd\u8907\u6578\u64da\u3002\u9019\u7a2e\u65b9\u6cd5\u5728\u8655\u7406\u8907\u96dc\u67e5\u8a62\u6642\u7279\u5225\u6709\u7528\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
WITH DuplicateRecords AS (\n    SELECT column_name, COUNT(*) AS count\n    FROM table_name\n    GROUP BY column_name\n    HAVING COUNT(*) > 1\n)\nSELECT *\nFROM DuplicateRecords;<\/code><\/pre>\n
\u9019\u500b\u67e5\u8a62\u9996\u5148\u5275\u5efa\u4e86\u4e00\u500b\u540d\u70baDuplicateRecords<\/code>\u7684CTE\uff0c\u7136\u5f8c\u5f9e\u4e2d\u9078\u64c7\u6240\u6709\u91cd\u8907\u7684\u6578\u64da\u689d\u76ee\u3002<\/p>\n
3. \u4f7f\u7528ROW_NUMBER()\u51fd\u6578<\/h3>\n
\u5982\u679c\u4f60\u60f3\u8981\u7372\u53d6\u6bcf\u500b\u91cd\u8907\u689d\u76ee\u7684\u5177\u9ad4\u884c\uff0c\u53ef\u4ee5\u4f7f\u7528ROW_NUMBER()<\/code>\u51fd\u6578\u3002\u9019\u6a23\u53ef\u4ee5\u70ba\u6bcf\u500b\u91cd\u8907\u7684\u689d\u76ee\u5206\u914d\u4e00\u500b\u552f\u4e00\u7684\u884c\u865f\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
WITH RankedRecords AS (\n    SELECT *, ROW_NUMBER() OVER (PARTITION BY column_name ORDER BY id) AS row_num\n    FROM table_name\n)\nSELECT *\nFROM RankedRecords\nWHERE row_num > 1;<\/code><\/pre>\n
\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0cPARTITION BY<\/code>\u5b50\u53e5\u7528\u65bc\u6839\u64dacolumn_name<\/code>\u5206\u7d44\uff0c\u4e26\u70ba\u6bcf\u7d44\u4e2d\u7684\u6bcf\u4e00\u884c\u5206\u914d\u4e00\u500b\u884c\u865f\u3002\u6700\u7d42\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u91cd\u8907\u7684\u689d\u76ee\uff0c\u884c\u865f\u5927\u65bc1\u7684\u689d\u76ee\u5373\u70ba\u91cd\u8907\u6578\u64da\u3002<\/p>\n
\u6e05\u7406\u91cd\u8907\u6578\u64da<\/h2>\n
\u4e00\u65e6\u8b58\u5225\u51fa\u91cd\u8907\u6578\u64da\uff0c\u63a5\u4e0b\u4f86\u7684\u6b65\u9a5f\u662f\u6e05\u7406\u9019\u4e9b\u6578\u64da\u3002\u9019\u53ef\u4ee5\u901a\u904e\u522a\u9664\u591a\u9918\u7684\u689d\u76ee\u6216\u5408\u4f75\u6578\u64da\u4f86\u5be6\u73fe\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u522a\u9664\u91cd\u8907\u6578\u64da\u7684\u793a\u4f8b\uff1a<\/p>\n
DELETE FROM table_name\nWHERE id NOT IN (\n    SELECT MIN(id)\n    FROM table_name\n    GROUP BY column_name\n);<\/code><\/pre>\n
\u9019\u500b\u67e5\u8a62\u5c07\u522a\u9664\u6240\u6709\u91cd\u8907\u7684\u689d\u76ee\uff0c\u53ea\u4fdd\u7559\u6bcf\u7d44\u4e2d\u7684\u6700\u5c0fID\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u5728DB2\u4e2d\u67e5\u627e\u548c\u8655\u7406\u91cd\u8907\u6578\u64da\u662f\u4e00\u500b\u91cd\u8981\u7684\u6578\u64da\u7ba1\u7406\u4efb\u52d9\u3002\u901a\u904e\u4f7f\u7528SQL\u67e5\u8a62\u4e2d\u7684GROUP BY<\/code>\u3001HAVING<\/code>\u3001CTE\u548cROW_NUMBER()<\/code>\u51fd\u6578\uff0c\u60a8\u53ef\u4ee5\u6709\u6548\u5730\u8b58\u5225\u548c\u6e05\u7406\u91cd\u8907\u6578\u64da\u3002\u9019\u4e0d\u50c5\u6709\u52a9\u65bc\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\uff0c\u9084\u80fd\u78ba\u4fdd\u6578\u64da\u7684\u4e00\u81f4\u6027\u548c\u6e96\u78ba\u6027\u3002<\/p>\n
\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528\u9999\u6e2fVPS<\/a>\u4f86\u6258\u7ba1\u60a8\u7684DB2\u6578\u64da\u5eab\uff0c\u9019\u5c07\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u548c\u53ef\u9760\u7684\u6027\u80fd\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528DB2\u67e5\u627e\u548c\u8655\u7406\u91cd\u8907\u6578\u64da\u5eab\u6578\u64da\uff0c\u63d0\u5347\u6578\u64da\u8cea\u91cf\u548c\u67e5\u8a62\u6548\u7387\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-175201","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/175201","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=175201"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/175201\/revisions"}],"predecessor-version":[{"id":175202,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/175201\/revisions\/175202"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=175201"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=175201"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=175201"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}