{"id":143803,"date":"2024-11-01T01:23:19","date_gmt":"2024-10-31T17:23:19","guid":{"rendered":"https:\/\/server.hk\/cnblog\/143803\/"},"modified":"2024-11-01T01:23:20","modified_gmt":"2024-10-31T17:23:20","slug":"sql-%e5%88%86%e7%b5%84%e5%8f%96%e6%9c%80%e5%be%8c%e4%b8%80%e6%a2%9d%ef%bc%9a%e5%84%aa%e5%8c%96%e6%95%b8%e6%93%9a%e5%ba%ab%e6%93%8d%e4%bd%9c-sql-%e5%88%86%e7%b5%84-%e6%9c%80%e5%be%8c%e4%b8%80%e6%a2%9d","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/143803\/","title":{"rendered":"SQL \u5206\u7d44\u53d6\u6700\u5f8c\u4e00\u689d\uff1a\u512a\u5316\u6578\u64da\u5eab\u64cd\u4f5c (sql \u5206\u7d44 \u6700\u5f8c\u4e00\u689d\u6578\u64da\u5eab)"},"content":{"rendered":"<h1 id=\"sql-%e5%88%86%e7%b5%84%e5%8f%96%e6%9c%80%e5%be%8c%e4%b8%80%e6%a2%9d%ef%bc%9a%e5%84%aa%e5%8c%96%e6%95%b8%e6%93%9a%e5%ba%ab%e6%93%8d%e4%bd%9c-RQJWuaAIiY\">SQL \u5206\u7d44\u53d6\u6700\u5f8c\u4e00\u689d\uff1a\u512a\u5316\u6578\u64da\u5eab\u64cd\u4f5c<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u5982\u4f55\u6709\u6548\u5730\u5f9e\u5927\u91cf\u6578\u64da\u4e2d\u63d0\u53d6\u6240\u9700\u4fe1\u606f\u662f\u4e00\u500b\u91cd\u8981\u7684\u8ab2\u984c\u3002\u7279\u5225\u662f\u5728\u8655\u7406\u5206\u7d44\u6578\u64da\u6642\uff0c\u7372\u53d6\u6bcf\u7d44\u7684\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u5e38\u5e38\u662f\u958b\u767c\u8005\u9762\u81e8\u7684\u6311\u6230\u4e4b\u4e00\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5982\u4f55\u4f7f\u7528 SQL \u8a9e\u53e5\u4f86\u5be6\u73fe\u5206\u7d44\u53d6\u6700\u5f8c\u4e00\u689d\u6578\u64da\u7684\u64cd\u4f5c\uff0c\u4e26\u63d0\u4f9b\u4e00\u4e9b\u512a\u5316\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u5efa\u8b70\u3002<\/p>\n<h2 id=\"%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-RQJWuaAIiY\">\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>\u5728 SQL \u4e2d\uff0c\u5206\u7d44\u64cd\u4f5c\u901a\u5e38\u4f7f\u7528 <code>GROUP BY<\/code> \u8a9e\u53e5\u4f86\u5be6\u73fe\u3002\u9019\u500b\u8a9e\u53e5\u53ef\u4ee5\u5c07\u6578\u64da\u6839\u64da\u67d0\u4e9b\u5217\u9032\u884c\u5206\u7d44\uff0c\u4e26\u5c0d\u6bcf\u7d44\u6578\u64da\u9032\u884c\u805a\u5408\u8a08\u7b97\u3002\u7136\u800c\uff0c\u7576\u6211\u5011\u9700\u8981\u7372\u53d6\u6bcf\u7d44\u7684\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u6642\uff0c\u50c5\u50c5\u4f7f\u7528 <code>GROUP BY<\/code> \u662f\u4e0d\u5920\u7684\u3002<\/p>\n<h2 id=\"%e7%8d%b2%e5%8f%96%e6%af%8f%e7%b5%84%e6%9c%80%e5%be%8c%e4%b8%80%e6%a2%9d%e8%a8%98%e9%8c%84%e7%9a%84%e6%96%b9%e6%b3%95-RQJWuaAIiY\">\u7372\u53d6\u6bcf\u7d44\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u7684\u65b9\u6cd5<\/h2>\n<p>\u7372\u53d6\u6bcf\u7d44\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u7684\u5e38\u898b\u65b9\u6cd5\u662f\u4f7f\u7528\u5b50\u67e5\u8a62\u6216\u7a97\u53e3\u51fd\u6578\u3002\u4ee5\u4e0b\u662f\u5169\u7a2e\u5e38\u898b\u7684\u5be6\u73fe\u65b9\u5f0f\uff1a<\/p>\n<h3 id=\"%e6%96%b9%e6%b3%95%e4%b8%80%ef%bc%9a%e4%bd%bf%e7%94%a8%e5%ad%90%e6%9f%a5%e8%a9%a2-RQJWuaAIiY\">\u65b9\u6cd5\u4e00\uff1a\u4f7f\u7528\u5b50\u67e5\u8a62<\/h3>\n<pre><code>\nSELECT t1.*\nFROM your_table t1\nWHERE t1.id = (\n    SELECT t2.id\n    FROM your_table t2\n    WHERE t2.group_column = t1.group_column\n    ORDER BY t2.timestamp_column DESC\n    LIMIT 1\n);\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c<code>your_table<\/code> \u662f\u6211\u5011\u7684\u6578\u64da\u8868\uff0c<code>group_column<\/code> \u662f\u6211\u5011\u7528\u4f86\u5206\u7d44\u7684\u5217\uff0c\u800c <code>timestamp_column<\/code> \u662f\u7528\u4f86\u78ba\u5b9a\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u7684\u6642\u9593\u6233\u5217\u3002\u9019\u500b\u67e5\u8a62\u9996\u5148\u9078\u64c7\u6bcf\u7d44\u7684\u6700\u5f8c\u4e00\u689d\u8a18\u9304\uff0c\u7136\u5f8c\u8fd4\u56de\u6574\u500b\u8a18\u9304\u3002<\/p>\n<h3 id=\"%e6%96%b9%e6%b3%95%e4%ba%8c%ef%bc%9a%e4%bd%bf%e7%94%a8%e7%aa%97%e5%8f%a3%e5%87%bd%e6%95%b8-RQJWuaAIiY\">\u65b9\u6cd5\u4e8c\uff1a\u4f7f\u7528\u7a97\u53e3\u51fd\u6578<\/h3>\n<pre><code>\nSELECT *\nFROM (\n    SELECT *,\n           ROW_NUMBER() OVER (PARTITION BY group_column ORDER BY timestamp_column DESC) as rn\n    FROM your_table\n) as subquery\nWHERE rn = 1;\n<\/code><\/pre>\n<p>\u9019\u7a2e\u65b9\u6cd5\u4f7f\u7528\u4e86\u7a97\u53e3\u51fd\u6578 <code>ROW_NUMBER()<\/code>\uff0c\u5b83\u70ba\u6bcf\u7d44\u7684\u8a18\u9304\u5206\u914d\u4e00\u500b\u5e8f\u865f\u3002\u7136\u5f8c\uff0c\u6211\u5011\u53ea\u9700\u9078\u64c7\u5e8f\u865f\u70ba 1 \u7684\u8a18\u9304\uff0c\u5373\u53ef\u7372\u5f97\u6bcf\u7d44\u7684\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u3002\u9019\u7a2e\u65b9\u6cd5\u901a\u5e38\u6bd4\u5b50\u67e5\u8a62\u66f4\u9ad8\u6548\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u6578\u64da\u96c6\u6642\u3002<\/p>\n<h2 id=\"%e5%84%aa%e5%8c%96%e6%95%b8%e6%93%9a%e5%ba%ab%e6%93%8d%e4%bd%9c%e7%9a%84%e5%bb%ba%e8%ad%b0-RQJWuaAIiY\">\u512a\u5316\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u5efa\u8b70<\/h2>\n<p>\u5728\u9032\u884c\u6578\u64da\u5eab\u64cd\u4f5c\u6642\uff0c\u6027\u80fd\u512a\u5316\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u512a\u5316\u5efa\u8b70\uff1a<\/p>\n<ul>\n<li><strong>\u7d22\u5f15\uff1a<\/strong>\u78ba\u4fdd\u5728 <code>group_column<\/code> \u548c <code>timestamp_column<\/code> \u4e0a\u5efa\u7acb\u7d22\u5f15\uff0c\u4ee5\u52a0\u5feb\u67e5\u8a62\u901f\u5ea6\u3002<\/li>\n<li><strong>\u907f\u514d SELECT *\uff1a<\/strong>\u5728\u67e5\u8a62\u4e2d\u660e\u78ba\u6307\u5b9a\u9700\u8981\u7684\u5217\uff0c\u9019\u6a23\u53ef\u4ee5\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002<\/li>\n<li><strong>\u5b9a\u671f\u6e05\u7406\u6578\u64da\uff1a<\/strong>\u5b9a\u671f\u522a\u9664\u4e0d\u5fc5\u8981\u7684\u6578\u64da\uff0c\u4ee5\u4fdd\u6301\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002<\/li>\n<li><strong>\u4f7f\u7528\u9069\u7576\u7684\u6578\u64da\u985e\u578b\uff1a<\/strong>\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u53ef\u4ee5\u6e1b\u5c11\u5b58\u5132\u7a7a\u9593\u548c\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-RQJWuaAIiY\">\u7d50\u8ad6<\/h2>\n<p>\u5728 SQL \u4e2d\u7372\u53d6\u6bcf\u7d44\u7684\u6700\u5f8c\u4e00\u689d\u8a18\u9304\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\uff0c\u901a\u904e\u4f7f\u7528\u5b50\u67e5\u8a62\u6216\u7a97\u53e3\u51fd\u6578\uff0c\u6211\u5011\u53ef\u4ee5\u6709\u6548\u5730\u5be6\u73fe\u9019\u4e00\u76ee\u6a19\u3002\u540c\u6642\uff0c\u901a\u904e\u9069\u7576\u7684\u512a\u5316\u63aa\u65bd\uff0c\u6211\u5011\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u5c07\u662f\u660e\u667a\u4e4b\u8209\uff0c\u56e0\u70ba\u5b83\u80fd\u63d0\u4f9b\u7a69\u5b9a\u7684\u6027\u80fd\u548c\u9748\u6d3b\u7684\u8cc7\u6e90\u914d\u7f6e\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22\u5982\u4f55\u5728 SQL \u4e2d\u6709\u6548\u5206\u7d44\u4e26\u63d0\u53d6\u6700\u5f8c\u4e00\u689d\u8a18\u9304\uff0c\u512a\u5316\u6578\u64da\u5eab\u64cd\u4f5c\uff0c\u63d0\u9ad8\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-143803","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143803","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=143803"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143803\/revisions"}],"predecessor-version":[{"id":143804,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/143803\/revisions\/143804"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=143803"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=143803"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=143803"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}