{"id":211,"date":"2026-01-23T06:48:51","date_gmt":"2026-01-23T06:48:51","guid":{"rendered":"https:\/\/blog.gpst.net.cn:4008\/?p=211"},"modified":"2026-01-28T06:24:15","modified_gmt":"2026-01-28T06:24:15","slug":"mysql%e8%bf%90%e7%bb%b4-%e6%9f%a5%e8%af%a2%e9%87%8d%e5%a4%8d%e6%95%b0%e6%8d%ae%e3%80%81%e5%88%a0%e9%99%a4%e9%87%8d%e5%a4%8d%e8%ae%b0%e5%bd%95","status":"publish","type":"post","link":"https:\/\/opshub.com.cn\/?p=211","title":{"rendered":"MySQL\u8fd0\u7ef4\u2014\u2014\u67e5\u8be2\u91cd\u590d\u6570\u636e\u3001\u5220\u9664\u91cd\u590d\u8bb0\u5f55"},"content":{"rendered":"\n<p>1\u3001\u5148\u786e\u8ba4\u91cd\u590d\u6570\u636e<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>-- \u67e5\u8be2\u91cd\u590d\u7684project+dept\u7ec4\u5408\u53ca\u91cd\u590d\u6570\u91cf\nSELECT \n    project,\n    dept,\n    COUNT(*) AS duplicate_count  -- \u7ed9\u8ba1\u6570\u7ed3\u679c\u52a0\u522b\u540d\uff0c\u4fbf\u4e8e\u7406\u89e3\nFROM projectdept \nGROUP BY project, dept \nHAVING COUNT(*) &gt; 1;<\/code><\/pre>\n\n\n\n<p>2\u3001\u5220\u9664\u91cd\u590d\u8bb0\u5f55\u7684\u8bed\u53e5<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>-- \u65b9\u5f0f1\uff1a\u4f7f\u7528JOIN+\u5b50\u67e5\u8be2\uff08\u63a8\u8350\uff0c\u517c\u5bb9\u6027\u597d\uff09\nDELETE t1 \nFROM projectdept AS t1\nINNER JOIN (\n    -- \u5148\u83b7\u53d6\u6bcf\u4e2aproject+dept\u7ec4\u5408\u7684\u6700\u5c0fID\n    SELECT project, dept, MIN(id) AS min_id\n    FROM projectdept\n    GROUP BY project, dept\n    HAVING COUNT(*) &gt; 1  -- \u53ea\u5904\u7406\u6709\u91cd\u590d\u7684\u7ec4\u5408\n) AS t2 \nON t1.project = t2.project \nAND t1.dept = t2.dept \nAND t1.id &gt; t2.min_id;  -- \u5220\u9664ID\u5927\u4e8e\u6700\u5c0fID\u7684\u91cd\u590d\u8bb0\u5f55\n\n-- \u65b9\u5f0f2\uff1a\u5982\u679c\u662fMySQL 8.0+\uff0c\u53ef\u7528\u7a97\u53e3\u51fd\u6570\uff08\u66f4\u7b80\u6d01\uff09\nDELETE FROM projectdept\nWHERE id IN (\n    SELECT id \n    FROM (\n        SELECT \n            id,\n            ROW_NUMBER() OVER (PARTITION BY project, dept ORDER BY id) AS rn\n        FROM projectdept\n    ) AS t\n    WHERE rn &gt; 1  -- \u4fdd\u7559rn=1\uff08ID\u6700\u5c0f\uff09\uff0c\u5220\u9664rn&gt;1\u7684\u91cd\u590d\u9879\n);<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>1\u3001\u5148\u786e\u8ba4\u91cd\u590d\u6570\u636e 2\u3001\u5220\u9664\u91cd\u590d\u8bb0\u5f55\u7684\u8bed\u53e5<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-211","post","type-post","status-publish","format-standard","hentry","category-8"],"_links":{"self":[{"href":"https:\/\/opshub.com.cn\/index.php?rest_route=\/wp\/v2\/posts\/211","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/opshub.com.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/opshub.com.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/opshub.com.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/opshub.com.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=211"}],"version-history":[{"count":2,"href":"https:\/\/opshub.com.cn\/index.php?rest_route=\/wp\/v2\/posts\/211\/revisions"}],"predecessor-version":[{"id":651,"href":"https:\/\/opshub.com.cn\/index.php?rest_route=\/wp\/v2\/posts\/211\/revisions\/651"}],"wp:attachment":[{"href":"https:\/\/opshub.com.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=211"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/opshub.com.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=211"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/opshub.com.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=211"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}