{"id":152235,"date":"2024-11-01T21:14:21","date_gmt":"2024-11-01T13:14:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/152235\/"},"modified":"2024-11-01T21:14:21","modified_gmt":"2024-11-01T13:14:21","slug":"%e4%b8%8d%e5%90%8c%e7%9a%84%e6%95%b8%e6%93%9a%e5%ba%ab%e5%b9%b3%e5%8f%b0%ef%bc%8c%e5%a6%82%e4%bd%95%e5%8f%96%e5%89%8d%e7%99%be%e5%88%86%e4%b9%8bn%e7%9a%84%e8%a8%98%e9%8c%84%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/152235\/","title":{"rendered":"\u4e0d\u540c\u7684\u6578\u64da\u5eab\u5e73\u53f0\uff0c\u5982\u4f55\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\uff1f"},"content":{"rendered":"

\u4e0d\u540c\u7684\u6578\u64da\u5eab\u5e73\u53f0\uff0c\u5982\u4f55\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\uff1f<\/h1>\n

\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0c\u63d0\u53d6\u7279\u5b9a\u6bd4\u4f8b\u7684\u8a18\u9304\u662f\u4e00\u500b\u5e38\u898b\u7684\u9700\u6c42\u3002\u7121\u8ad6\u662f\u70ba\u4e86\u6578\u64da\u5206\u6790\u3001\u5831\u544a\u751f\u6210\u9084\u662f\u5176\u4ed6\u76ee\u7684\uff0c\u4e86\u89e3\u5982\u4f55\u5728\u4e0d\u540c\u7684\u6578\u64da\u5eab\u5e73\u53f0\u4e0a\u5be6\u73fe\u9019\u4e00\u529f\u80fd\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u5e7e\u7a2e\u4e3b\u6d41\u6578\u64da\u5eab\u5e73\u53f0\uff08\u5982 MySQL\u3001PostgreSQL \u548c SQL Server\uff09\u4e2d\uff0c\u5982\u4f55\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\u3002<\/p>\n

MySQL<\/h2>\n

\u5728 MySQL \u4e2d\uff0c\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\u53ef\u4ee5\u901a\u904e\u4ee5\u4e0b\u6b65\u9a5f\u5be6\u73fe\uff1a<\/p>\n

    \n
  1. \u9996\u5148\uff0c\u8a08\u7b97\u7e3d\u8a18\u9304\u6578\u3002<\/li>\n
  2. \u7136\u5f8c\uff0c\u6839\u64da\u6240\u9700\u7684\u767e\u5206\u6bd4\u8a08\u7b97\u51fa\u8981\u63d0\u53d6\u7684\u8a18\u9304\u6578\u3002<\/li>\n
  3. \u6700\u5f8c\uff0c\u4f7f\u7528 LIMIT<\/code> \u5b50\u53e5\u4f86\u9650\u5236\u67e5\u8a62\u7d50\u679c\u3002<\/li>\n<\/ol>\n

    \u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff0c\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba employees<\/code> \u7684\u8868\uff0c\u4e26\u5e0c\u671b\u63d0\u53d6\u524d 10% \u7684\u8a18\u9304\uff1a<\/p>\n

    SELECT * FROM employees\nORDER BY id\nLIMIT (SELECT COUNT(*) * 0.1 FROM employees);<\/code><\/pre>\n
    \u9700\u8981\u6ce8\u610f\u7684\u662f\uff0cMySQL \u4e0d\u652f\u6301\u5728 LIMIT<\/code> \u4e2d\u76f4\u63a5\u4f7f\u7528\u5b50\u67e5\u8a62\uff0c\u56e0\u6b64\u9700\u8981\u5148\u8a08\u7b97\u51fa\u6578\u91cf\uff0c\u518d\u57f7\u884c\u67e5\u8a62\u3002<\/p>\n
    PostgreSQL<\/h2>\n
    \u5728 PostgreSQL \u4e2d\uff0c\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\u7684\u904e\u7a0b\u8207 MySQL \u985e\u4f3c\uff0c\u4f46\u53ef\u4ee5\u4f7f\u7528\u66f4\u9748\u6d3b\u7684\u7a97\u53e3\u51fd\u6578\u4f86\u5be6\u73fe\uff1a<\/p>\n
    WITH ranked_employees AS (\n    SELECT *, \n           NTILE(100) OVER (ORDER BY id) AS percentile\n    FROM employees\n)\nSELECT * FROM ranked_employees\nWHERE percentile <= 10;<\/code><\/pre>\n
    \u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u4f7f\u7528\u4e86 NTILE<\/code> \u51fd\u6578\u5c07\u8a18\u9304\u5206\u6210 100 \u500b\u6876\uff0c\u7136\u5f8c\u9078\u64c7\u524d 10% \u7684\u8a18\u9304\u3002<\/p>\n
    SQL Server<\/h2>\n
    \u5728 SQL Server \u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528 TOP<\/code> \u95dc\u9375\u5b57\u4f86\u63d0\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u793a\u4f8b\uff1a<\/p>\n
    DECLARE @TotalCount INT;\nSELECT @TotalCount = COUNT(*) FROM employees;\n\nSELECT TOP (@TotalCount * 0.1) *\nFROM employees\nORDER BY id;<\/code><\/pre>\n
    \u9019\u88e1\uff0c\u6211\u5011\u9996\u5148\u8a08\u7b97\u7e3d\u8a18\u9304\u6578\uff0c\u7136\u5f8c\u4f7f\u7528 TOP<\/code> \u4f86\u9650\u5236\u67e5\u8a62\u7d50\u679c\u3002<\/p>\n
    SQLite<\/h2>\n
    \u5728 SQLite \u4e2d\uff0c\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\u53ef\u4ee5\u4f7f\u7528 LIMIT<\/code>\uff0c\u4f46\u9700\u8981\u5148\u8a08\u7b97\u7e3d\u6578\uff1a<\/p>\n
    SELECT * FROM employees\nLIMIT (SELECT COUNT(*) * 0.1 FROM employees);<\/code><\/pre>\n
    \u9019\u88e1\u7684\u9650\u5236\u8207 MySQL \u985e\u4f3c\uff0c\u9700\u5148\u8a08\u7b97\u51fa\u8981\u63d0\u53d6\u7684\u8a18\u9304\u6578\u3002<\/p>\n
    \u7e3d\u7d50<\/h2>\n
    \u4e0d\u540c\u7684\u6578\u64da\u5eab\u5e73\u53f0\u5728\u63d0\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\u6642\u6709\u5404\u81ea\u7684\u8a9e\u6cd5\u548c\u65b9\u6cd5\u3002\u7121\u8ad6\u662f\u4f7f\u7528 LIMIT<\/code>\u3001TOP<\/code> \u9084\u662f\u7a97\u53e3\u51fd\u6578\uff0c\u4e86\u89e3\u9019\u4e9b\u5dee\u7570\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u6709\u6548\u5730\u9032\u884c\u6578\u64da\u64cd\u4f5c\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u4f01\u696d\uff0c\u9078\u64c7\u5408\u9069\u7684 VPS<\/a> \u65b9\u6848\u4f86\u904b\u884c\u9019\u4e9b\u6578\u64da\u5eab\u662f\u81f3\u95dc\u91cd\u8981\u7684\u3002\u7121\u8ad6\u662f \u9999\u6e2fVPS<\/a> \u9084\u662f\u5176\u4ed6\u5730\u5340\u7684\u670d\u52d9\uff0c\u78ba\u4fdd\u9078\u64c7\u4e00\u500b\u7a69\u5b9a\u4e14\u6027\u80fd\u512a\u8d8a\u7684 \u4f3a\u670d\u5668<\/a> \u5c0d\u65bc\u6578\u64da\u5eab\u7684\u904b\u884c\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
    \u63a2\u7d22\u4e0d\u540c\u6578\u64da\u5eab\u5e73\u53f0\u4e2d\uff0c\u5982\u4f55\u6709\u6548\u63d0\u53d6\u524d\u767e\u5206\u4e4bN\u7684\u8a18\u9304\uff0c\u63d0\u5347\u6578\u64da\u5206\u6790\u6548\u7387\u8207\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-152235","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/152235","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=152235"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/152235\/revisions"}],"predecessor-version":[{"id":152236,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/152235\/revisions\/152236"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=152235"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=152235"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=152235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}