{"id":76300,"date":"2024-10-16T05:31:13","date_gmt":"2024-10-15T21:31:13","guid":{"rendered":"https:\/\/server.hk\/cnblog\/76300\/"},"modified":"2024-10-16T05:31:13","modified_gmt":"2024-10-15T21:31:13","slug":"mysql%e5%88%aa%e9%99%a4%e9%87%8d%e8%a4%87%e8%a8%98%e9%8c%84%e7%9a%84%e5%b8%b8%e7%94%a8%e6%96%b9%e6%b3%95","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/76300\/","title":{"rendered":"MySQL\u522a\u9664\u91cd\u8907\u8a18\u9304\u7684\u5e38\u7528\u65b9\u6cd5"},"content":{"rendered":"

MySQL\u522a\u9664\u91cd\u8907\u8a18\u9304\u7684\u5e38\u7528\u65b9\u6cd5<\/h1>\n

\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u91cd\u8907\u8a18\u9304\u662f\u4e00\u500b\u5e38\u898b\u7684\u554f\u984c\uff0c\u7279\u5225\u662f\u5728\u4f7f\u7528MySQL\u6642\u3002\u91cd\u8907\u7684\u6578\u64da\u4e0d\u50c5\u6703\u4f54\u7528\u5b58\u5132\u7a7a\u9593\uff0c\u9084\u53ef\u80fd\u5c0e\u81f4\u67e5\u8a62\u7d50\u679c\u7684\u4e0d\u6e96\u78ba\u3002\u56e0\u6b64\uff0c\u4e86\u89e3\u5982\u4f55\u6709\u6548\u5730\u522a\u9664\u91cd\u8907\u8a18\u9304\u662f\u6bcf\u4f4d\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u5fc5\u9808\u638c\u63e1\u7684\u6280\u80fd\u3002\u672c\u6587\u5c07\u4ecb\u7d39\u5e7e\u7a2e\u5e38\u7528\u7684\u65b9\u6cd5\u4f86\u522a\u9664MySQL\u4e2d\u7684\u91cd\u8907\u8a18\u9304\u3002<\/p>\n

\u65b9\u6cd5\u4e00\uff1a\u4f7f\u7528GROUP BY\u548cHAVING\u5b50\u53e5<\/h2>\n

\u9019\u7a2e\u65b9\u6cd5\u5229\u7528\u4e86SQL\u7684\u805a\u5408\u51fd\u6578\uff0c\u901a\u904e\u5206\u7d44\u548c\u904e\u6ffe\u4f86\u8b58\u5225\u91cd\u8907\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n

DELETE FROM your_table\nWHERE id NOT IN (\n    SELECT id FROM (\n        SELECT MIN(id) as id\n        FROM your_table\n        GROUP BY column1, column2\n    ) as temp\n);<\/code><\/pre>\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c`your_table`\u662f\u4f60\u7684\u6578\u64da\u8868\uff0c`column1`\u548c`column2`\u662f\u4f60\u5e0c\u671b\u6aa2\u67e5\u91cd\u8907\u7684\u5217\u3002\u9019\u6bb5\u4ee3\u78bc\u6703\u4fdd\u7559\u6bcf\u7d44\u91cd\u8907\u8a18\u9304\u4e2d\u7684\u6700\u5c0fID\uff0c\u4e26\u522a\u9664\u5176\u4ed6\u91cd\u8907\u7684\u8a18\u9304\u3002<\/p>\n
\u65b9\u6cd5\u4e8c\uff1a\u4f7f\u7528ROW_NUMBER()\u51fd\u6578<\/h2>\n
\u5982\u679c\u4f60\u7684MySQL\u7248\u672c\u652f\u6301\u7a97\u53e3\u51fd\u6578\uff08MySQL 8.0\u53ca\u4ee5\u4e0a\uff09\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528`ROW_NUMBER()`\u4f86\u6a19\u8a18\u91cd\u8907\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u793a\u4f8b\u4ee3\u78bc\uff1a<\/p>\n
WITH cte AS (\n    SELECT *,\n           ROW_NUMBER() OVER (PARTITION BY column1, column2 ORDER BY id) as row_num\n    FROM your_table\n)\nDELETE FROM cte WHERE row_num > 1;<\/code><\/pre>\n
\u9019\u6bb5\u4ee3\u78bc\u6703\u70ba\u6bcf\u7d44\u91cd\u8907\u8a18\u9304\u5206\u914d\u4e00\u500b\u884c\u865f\uff0c\u7136\u5f8c\u522a\u9664\u884c\u865f\u5927\u65bc1\u7684\u8a18\u9304\uff0c\u5f9e\u800c\u4fdd\u7559\u6bcf\u7d44\u7684\u7b2c\u4e00\u689d\u8a18\u9304\u3002<\/p>\n
\u65b9\u6cd5\u4e09\uff1a\u4f7f\u7528JOIN\u8a9e\u53e5<\/h2>\n
\u53e6\u4e00\u7a2e\u522a\u9664\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5\u662f\u4f7f\u7528JOIN\u8a9e\u53e5\u3002\u9019\u7a2e\u65b9\u6cd5\u53ef\u4ee5\u5728\u4e0d\u4f7f\u7528\u5b50\u67e5\u8a62\u7684\u60c5\u6cc1\u4e0b\u9054\u5230\u76f8\u540c\u7684\u6548\u679c\u3002\u4ee5\u4e0b\u662f\u793a\u4f8b\uff1a<\/p>\n
DELETE t1\nFROM your_table t1\nJOIN your_table t2 \nON t1.column1 = t2.column1 AND t1.column2 = t2.column2\nWHERE t1.id > t2.id;<\/code><\/pre>\n
\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c`t1`\u548c`t2`\u662f\u540c\u4e00\u500b\u8868\u7684\u5225\u540d\u3002\u9019\u6bb5\u4ee3\u78bc\u6703\u522a\u9664ID\u8f03\u5927\u7684\u91cd\u8907\u8a18\u9304\uff0c\u5f9e\u800c\u4fdd\u7559ID\u8f03\u5c0f\u7684\u8a18\u9304\u3002<\/p>\n
\u65b9\u6cd5\u56db\uff1a\u4f7f\u7528DISTINCT\u548cINSERT INTO<\/h2>\n
\u5982\u679c\u4f60\u5e0c\u671b\u4fdd\u7559\u91cd\u8907\u8a18\u9304\u7684\u67d0\u4e9b\u4fe1\u606f\uff0c\u53ef\u4ee5\u8003\u616e\u4f7f\u7528`DISTINCT`\u4f86\u5275\u5efa\u4e00\u500b\u65b0\u7684\u8868\uff0c\u7136\u5f8c\u5c07\u552f\u4e00\u8a18\u9304\u63d2\u5165\u5230\u9019\u500b\u65b0\u8868\u4e2d\u3002\u4ee5\u4e0b\u662f\u793a\u4f8b\uff1a<\/p>\n
CREATE TABLE new_table AS\nSELECT DISTINCT column1, column2\nFROM your_table;<\/code><\/pre>\n
\u9019\u6a23\uff0c\u4f60\u5c31\u53ef\u4ee5\u5728`new_table`\u4e2d\u7372\u5f97\u552f\u4e00\u7684\u8a18\u9304\uff0c\u7136\u5f8c\u53ef\u4ee5\u9078\u64c7\u522a\u9664\u539f\u59cb\u8868\u4e2d\u7684\u91cd\u8907\u8a18\u9304\u3002<\/p>\n
\u7e3d\u7d50<\/h2>\n
\u5728MySQL\u4e2d\u522a\u9664\u91cd\u8907\u8a18\u9304\u7684\u65b9\u6cd5\u6709\u5f88\u591a\uff0c\u9078\u64c7\u5408\u9069\u7684\u65b9\u6cd5\u53d6\u6c7a\u65bc\u5177\u9ad4\u7684\u9700\u6c42\u548c\u6578\u64da\u7d50\u69cb\u3002\u7121\u8ad6\u662f\u4f7f\u7528\u805a\u5408\u51fd\u6578\u3001\u7a97\u53e3\u51fd\u6578\u3001JOIN\u8a9e\u53e5\u9084\u662fDISTINCT\uff0c\u4e86\u89e3\u9019\u4e9b\u6280\u8853\u90fd\u80fd\u5e6b\u52a9\u4f60\u66f4\u6709\u6548\u5730\u7ba1\u7406\u6578\u64da\u5eab\u3002<\/p>\n
\u5982\u679c\u4f60\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684\u6578\u64da\u5eab\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528\u9999\u6e2fVPS<\/a>\u4f86\u63d0\u5347\u4f60\u7684\u6578\u64da\u8655\u7406\u80fd\u529b\u3002\u7121\u8ad6\u662f\u6578\u64da\u5eab\u7ba1\u7406\u9084\u662f\u5176\u4ed6\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684\u4f3a\u670d\u5668<\/a>\u80fd\u5920\u986f\u8457\u63d0\u9ad8\u4f60\u7684\u5de5\u4f5c\u6548\u7387\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22MySQL\u4e2d\u522a\u9664\u91cd\u8907\u8a18\u9304\u7684\u5e38\u7528\u65b9\u6cd5\uff0c\u63d0\u5347\u6578\u64da\u5eab\u6548\u7387\uff0c\u78ba\u4fdd\u6578\u64da\u7684\u6e96\u78ba\u6027\u8207\u4e00\u81f4\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-76300","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76300","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=76300"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76300\/revisions"}],"predecessor-version":[{"id":76301,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/76300\/revisions\/76301"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=76300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=76300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=76300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}