{"id":201061,"date":"2025-05-06T11:28:20","date_gmt":"2025-05-06T03:28:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/201061\/"},"modified":"2025-05-06T11:28:20","modified_gmt":"2025-05-06T03:28:20","slug":"%e5%a6%82%e4%bd%95%e5%90%88%e5%b9%b6%e5%a4%9a%e4%b8%aa%e5%8c%85%e5%90%ab%e7%9b%b8%e5%90%8c%e6%9f%a5%e8%af%a2%e6%a8%a1%e5%bc%8f%e7%9a%84-sql-%e8%af%ad%e5%8f%a5%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/201061\/","title":{"rendered":"\u5982\u4f55\u5408\u5e76\u591a\u4e2a\u5305\u542b\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 SQL \u8bed\u53e5\uff1f"},"content":{"rendered":"

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\u5982\u4f55\u5408\u5e76\u591a\u4e2a\u5305\u542b\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 SQL \u8bed\u53e5\uff1f<\/h1>\n

\u7f16\u7a0b\u5e76\u4e0d\u662f\u4e00\u4e2a\u673a\u68b0\u6027\u7684\u5de5\u4f5c\uff0c\u800c\u662f\u9700\u8981\u6709\u601d\u8003\uff0c\u6709\u521b\u65b0\u7684\u5de5\u4f5c\uff0c\u8bed\u6cd5\u662f\u56fa\u5b9a\u7684\uff0c\u4f46\u89e3\u51b3\u95ee\u9898\u7684\u601d\u8def\u5219\u662f\u4f9d\u9760\u4eba\u7684\u601d\u7ef4\uff0c\u8fd9\u5c31\u9700\u8981\u6211\u4eec\u575a\u6301\u5b66\u4e60\u548c\u66f4\u65b0\u81ea\u5df1\u7684\u77e5\u8bc6\u3002\u4eca\u5929\u4e3b\u673a\u5b9d\u8d1d\u5c31\u6574\u7406\u5206\u4eab\u300a\u5982\u4f55\u5408\u5e76\u591a\u4e2a\u5305\u542b\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 SQL \u8bed\u53e5\uff1f\u300b\uff0c\u6587\u7ae0\u8bb2\u89e3\u7684\u77e5\u8bc6\u70b9\u4e3b\u8981\u5305\u62ec\uff0c\u5982\u679c\u4f60\u5bf9\u6570\u636e\u5e93\u65b9\u9762\u7684\u77e5\u8bc6\u70b9\u611f\u5174\u8da3\uff0c\u5c31\u4e0d\u8981\u9519\u8fc7\u4e3b\u673a\u5b9d\u8d1d\uff0c\u5728\u8fd9\u53ef\u4ee5\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff0c\u52a9\u529b\u5f00\u53d1\u80fd\u529b\u7684\u63d0\u5347\u3002<\/p>\n

<\/p>\n

\u5982\u4f55\u5408\u5e76\u591a\u4e2a\u5305\u542b\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 sql \u8bed\u53e5\uff1f<\/strong><\/p>\n

\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u9700\u8981\u5bf9\u540c\u4e00\u5f20\u8868\u6267\u884c\u591a\u4e2a\u5177\u6709\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 sql \u8bed\u53e5\u3002\u4f20\u7edf\u7684\u89e3\u51b3\u65b9\u6848\u662f\u7f16\u5199\u591a\u6761\u5355\u72ec\u7684\u8bed\u53e5\uff0c\u4f46\u8fd9\u53ef\u80fd\u5f88\u7e41\u7410\u4e14\u5bb9\u6613\u51fa\u9519\u3002\u672c\u6587\u5c06\u4ecb\u7ecd\u4e24\u79cd\u65b9\u6cd5\uff0c\u5c06\u591a\u4e2a sql \u8bed\u53e5\u5408\u5e76\u4e3a\u4e00\u4e2a\u66f4\u7b80\u6d01\u3001\u66f4\u5f3a\u5927\u7684\u67e5\u8be2\u3002<\/p>\n

\u65b9\u6cd5 1\uff1a\u57fa\u4e8e\u7a97\u53e3\u51fd\u6570\uff08mysql >= 8.0\uff09<\/strong><\/p>\n

\u5982\u4eca\u7248\u672c\u7684 mysql\uff088.0 \u53ca\u66f4\u9ad8\u7248\u672c\uff09\u652f\u6301\u7a97\u53e3\u51fd\u6570\uff0c\u8fd9\u5141\u8bb8\u6211\u4eec\u5bf9\u884c\u7ec4\u6267\u884c\u8ba1\u7b97\u5e76\u6309\u884c\u5bf9\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\u3002\u5bf9\u4e8e\u7ed9\u5b9a\u7684\u95ee\u9898\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n

with ranked_data as (\n    select *,\n           count(*) over (partition by title, mark) as count,\n           row_number() over (partition by mark order by count(*) desc) as row_num\n    from t_search\n    where mark between 'a' and 'z'\n    group by title, mark\n)\nselect *\nfrom ranked_data\nwhere row_num <= 20\norder by mark, count desc;<\/pre>\n
\u6b64\u67e5\u8be2\u4f7f\u7528\u7a97\u53e3\u51fd\u6570 count() \u548c row_number() \u8ba1\u7b97\u6bcf\u4e2a\u6807\u9898-\u6807\u8bb0\u5bf9\u7684\u8ba1\u6570\u548c\u884c\u53f7\u3002\u7136\u540e\uff0c\u5b83\u4ec5\u9009\u62e9\u524d 20 \u884c\uff08\u5bf9\u4e8e\u6bcf\u4e2a\u6807\u8bb0\uff09\u5e76\u6309\u6807\u8bb0\u548c\u8ba1\u6570\u9012\u51cf\u987a\u5e8f\u6392\u5e8f\u3002<\/p>\n
\u65b9\u6cd5 2\uff1a\u57fa\u4e8e\u53d8\u91cf\uff08mysql < 8.0\uff09<\/strong><\/p>\n
\u5bf9\u4e8e\u4e0d\u652f\u6301\u7a97\u53e3\u51fd\u6570\u7684 mysql \u7248\u672c\uff08\u4f4e\u4e8e 8.0\uff09\uff0c\u53e6\u4e00\u79cd\u65b9\u6cd5\u662f\u4f7f\u7528\u53d8\u91cf\u6765\u8ddf\u8e2a\u67e5\u8be2\u4e2d\u7684\u72b6\u6001\u3002\u4ee5\u4e0b\u67e5\u8be2\u4f7f\u7528\u6b64\u6280\u672f\uff1a<\/p>\n
SELECT * \nFROM (\n    SELECT *,\n           @rank := IF(@prev_mark = mark, @rank + 1, 1) AS rank,\n           @prev_mark := mark,\n           COUNT(*) AS count\n    FROM t_search\n    JOIN (SELECT @rank := 0, @prev_mark := '') AS vars\n    WHERE mark BETWEEN 'a' AND 'z'\n    GROUP BY title, mark\n    ORDER BY mark, count DESC\n) AS ranked_data\nWHERE rank <= 20\nORDER BY mark, count DESC;<\/pre>\n
\u6b64\u67e5\u8be2\u4f7f\u7528\u7528\u6237\u5b9a\u4e49\u53d8\u91cf @rank \u548c @prev_mark \u6765\u8ddf\u8e2a\u6bcf\u4e2a\u6807\u8bb0\u7684\u5f53\u524d\u6392\u540d\u548c\u4ee5\u524d\u9047\u5230\u7684\u6807\u8bb0\u3002\u7136\u540e\uff0c\u5b83\u6309\u6807\u8bb0\u548c\u8ba1\u6570\u9012\u51cf\u987a\u5e8f\u5bf9\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\uff0c\u5e76\u4ec5\u9009\u62e9\u524d 20 \u884c\u3002<\/p>\n
\u8fd9\u4e24\u79cd\u65b9\u6cd5\u90fd\u53ef\u4ee5\u5c06\u591a\u4e2a sql \u8bed\u53e5\u5408\u5e76\u4e3a\u4e00\u4e2a\u66f4\u7b80\u6d01\u3001\u66f4\u6709\u6548\u7684\u67e5\u8be2\uff0c\u4ece\u800c\u7b80\u5316\u4e86\u4ee3\u7801\u5e76\u63d0\u9ad8\u4e86\u6027\u80fd\u3002<\/p>\n
\u4eca\u5929\u5173\u4e8e\u300a\u5982\u4f55\u5408\u5e76\u591a\u4e2a\u5305\u542b\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 SQL \u8bed\u53e5\uff1f\u300b\u7684\u5185\u5bb9\u5c31\u4ecb\u7ecd\u5230\u8fd9\u91cc\u4e86\uff0c\u662f\u4e0d\u662f\u5b66\u8d77\u6765\u4e00\u76ee\u4e86\u7136\uff01\u60f3\u8981\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u5185\u5bb9\u8bf7\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff01<\/p>\n
\n
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\u5982\u4f55\u5408\u5e76\u591a\u4e2a\u5305\u542b\u76f8\u540c\u67e5\u8be2\u6a21\u5f0f\u7684 ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-201061","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201061","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"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=201061"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201061\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=201061"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=201061"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=201061"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}