{"id":199695,"date":"2025-05-06T09:45:57","date_gmt":"2025-05-06T01:45:57","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199695\/"},"modified":"2025-05-06T09:45:57","modified_gmt":"2025-05-06T01:45:57","slug":"%e4%bd%bf%e7%94%a8distinct%e5%85%b3%e9%94%ae%e5%ad%97%e5%9c%a8sql%e4%b8%ad%e5%8e%bb%e9%87%8d","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199695\/","title":{"rendered":"\u4f7f\u7528DISTINCT\u5173\u952e\u5b57\u5728SQL\u4e2d\u53bb\u91cd"},"content":{"rendered":"

<\/b> <\/p>\n

\u4f7f\u7528DISTINCT\u5173\u952e\u5b57\u5728SQL\u4e2d\u53bb\u91cd<\/h1>\n

\u4ece\u73b0\u5728\u5f00\u59cb\uff0c\u52aa\u529b\u5b66\u4e60\u5427\uff01\u672c\u6587\u4e3b\u8981\u8bb2\u89e3\u4e86\u7b49\u7b49\u76f8\u5173\u77e5\u8bc6\u70b9\uff0c\u6211\u4f1a\u5728\u4e3b\u673a\u5b9d\u8d1d\u4e2d\u6301\u7eed\u66f4\u65b0\u76f8\u5173\u7684\u7cfb\u5217\u6587\u7ae0\uff0c\u6b22\u8fce\u5927\u5bb6\u5173\u6ce8\u5e76\u79ef\u6781\u7559\u8a00\u5efa\u8bae\u3002\u4e0b\u9762\u5c31\u5148\u4e00\u8d77\u6765\u770b\u4e00\u4e0b\u672c\u7bc7\u6b63\u6587\u5185\u5bb9\u5427\uff0c\u5e0c\u671b\u80fd\u5e2e\u5230\u4f60\uff01<\/p>\n

SQL\u4e2ddistinct\u7528\u6cd5\uff0c\u9700\u8981\u5177\u4f53\u4ee3\u7801\u793a\u4f8b<\/p>\n

\u5728SQL\u4e2d\uff0cDISTINCT\u5173\u952e\u5b57\u7528\u4e8e\u53bb\u9664\u67e5\u8be2\u7ed3\u679c\u4e2d\u91cd\u590d\u7684\u884c\uff0c\u53ea\u8fd4\u56de\u552f\u4e00\u7684\u884c\u3002\u8fd9\u5bf9\u4e8e\u9700\u8981\u7edf\u8ba1\u4e0d\u540c\u503c\u6216\u8005\u53bb\u91cd\u7684\u60c5\u51b5\u975e\u5e38\u6709\u7528\u3002DISTINCT\u53ef\u4ee5\u5e94\u7528\u4e8eSELECT\u8bed\u53e5\u4e2d\u7684\u4e00\u4e2a\u6216\u591a\u4e2a\u5217\u3002\u4e0b\u9762\u5c06\u8be6\u7ec6\u4ecb\u7ecd\u5982\u4f55\u4f7f\u7528DISTINCT\u5173\u952e\u5b57\uff0c\u5e76\u63d0\u4f9b\u4e00\u4e9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002<\/p>\n

    \n
  1. \u57fa\u672c\u7528\u6cd5<\/li>\n<\/ol>\n

    \u4f7f\u7528DISTINCT\u5173\u952e\u5b57\u7684\u57fa\u672c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

    SELECT DISTINCT \u5217\u540d FROM \u8868\u540d;<\/pre>\n
    \u5176\u4e2d\uff0c\u5217\u540d\u662f\u8981\u53bb\u91cd\u7684\u5217\uff0c\u8868\u540d\u662f\u8981\u67e5\u8be2\u7684\u8868\u540d\u3002\u4e0b\u9762\u901a\u8fc7\u4e00\u4e2a\u5177\u4f53\u7684\u4f8b\u5b50\u6765\u6f14\u793a\u5176\u7528\u6cd5\u3002<\/p>\n
    \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u5b66\u751f\u8868students<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u6bcf\u4e2a\u5b66\u751f\u7684\u59d3\u540d\u548c\u5e74\u9f84\u3002\u6211\u4eec\u5e0c\u671b\u5f97\u5230\u4e0d\u91cd\u590d\u7684\u5e74\u9f84\u503c\u3002\u53ef\u4ee5\u4f7f\u7528\u5982\u4e0bSQL\u8bed\u53e5\uff1a<\/p>\n
    SELECT DISTINCT age FROM students;<\/pre>\n
    \u8be5\u8bed\u53e5\u5c06\u8fd4\u56de\u4e00\u4e2a\u7ed3\u679c\u96c6\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u6240\u6709\u4e0d\u91cd\u590d\u7684\u5e74\u9f84\u503c\u3002<\/p>\n
      \n
    1. \u591a\u5217\u53bb\u91cd<\/li>\n<\/ol>\n
      \u5982\u679c\u9700\u8981\u6839\u636e\u591a\u5217\u8fdb\u884c\u53bb\u91cd\uff0c\u53ea\u9700\u8981\u5728SELECT\u8bed\u53e5\u4e2d\u63d0\u4f9b\u591a\u4e2a\u5217\u540d\u5373\u53ef\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n
      SELECT DISTINCT column1, column2 FROM table_name;<\/pre>\n
      \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u8ba2\u5355\u8868orders<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u8ba2\u5355\u53f7\u3001\u5ba2\u6237\u59d3\u540d\u548c\u8ba2\u5355\u91d1\u989d\u3002\u6211\u4eec\u5e0c\u671b\u6839\u636e\u5ba2\u6237\u59d3\u540d\u548c\u8ba2\u5355\u91d1\u989d\u8fdb\u884c\u53bb\u91cd\uff0c\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n
      SELECT DISTINCT customer_name, order_amount FROM orders;<\/pre>\n
      \u8be5\u8bed\u53e5\u5c06\u8fd4\u56de\u4e00\u4e2a\u7ed3\u679c\u96c6\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u4e0d\u91cd\u590d\u7684\u5ba2\u6237\u59d3\u540d\u548c\u8ba2\u5355\u91d1\u989d\u7684\u7ec4\u5408\u3002<\/p>\n
        \n
      1. \u53bb\u91cd\u540e\u7684\u6392\u5e8f<\/li>\n<\/ol>\n
        \u5728\u67e5\u8be2\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u5bf9\u53bb\u91cd\u540e\u7684\u7ed3\u679c\u8fdb\u884c\u6392\u5e8f\u3002\u4f7f\u7528ORDER BY\u5173\u952e\u5b57\uff0c\u53ef\u4ee5\u6309\u7167\u6307\u5b9a\u7684\u5217\u8fdb\u884c\u5347\u5e8f\u6216\u964d\u5e8f\u6392\u5e8f\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n
        SELECT DISTINCT column_name FROM table_name ORDER BY column_name ASC\/DESC;<\/pre>\n
        \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u5546\u54c1\u8868products<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u5546\u54c1ID\u3001\u5546\u54c1\u540d\u79f0\u548c\u4ef7\u683c\u3002\u6211\u4eec\u5e0c\u671b\u5f97\u5230\u4e0d\u91cd\u590d\u7684\u5546\u54c1\u540d\u79f0\uff0c\u5e76\u6309\u7167\u4ef7\u683c\u7684\u964d\u5e8f\u8fdb\u884c\u6392\u5e8f\uff0c\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n
        SELECT DISTINCT product_name FROM products ORDER BY price DESC;<\/pre>\n
        \u8be5\u8bed\u53e5\u5c06\u8fd4\u56de\u4e00\u4e2a\u7ed3\u679c\u96c6\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u4e0d\u91cd\u590d\u7684\u5546\u54c1\u540d\u79f0\uff0c\u5e76\u6309\u7167\u4ef7\u683c\u7684\u964d\u5e8f\u8fdb\u884c\u6392\u5e8f\u3002<\/p>\n
          \n
        1. \u53bb\u91cd\u540e\u7684\u8ba1\u6570<\/li>\n<\/ol>\n
          \u6709\u65f6\u5019\uff0c\u6211\u4eec\u5e0c\u671b\u77e5\u9053\u53bb\u91cd\u540e\u7684\u7ed3\u679c\u96c6\u4e2d\u6709\u591a\u5c11\u884c\u3002\u53ef\u4ee5\u4f7f\u7528COUNT\u51fd\u6570\u6765\u5b9e\u73b0\u8fd9\u4e2a\u76ee\u7684\u3002\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\uff1a<\/p>\n
          SELECT COUNT(DISTINCT column_name) FROM table_name;<\/pre>\n
          \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u5458\u5de5\u8868employees<\/code>\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u5458\u5de5ID\u548c\u6240\u5728\u90e8\u95e8\u3002\u6211\u4eec\u5e0c\u671b\u77e5\u9053\u53bb\u91cd\u540e\u7684\u90e8\u95e8\u6570\u76ee\uff0c\u4e0b\u9762\u662f\u4e00\u4e2a\u793a\u4f8b\u4ee3\u7801\uff1a<\/p>\n
          SELECT COUNT(DISTINCT department) FROM employees;<\/pre>\n
          \u8be5\u8bed\u53e5\u5c06\u8fd4\u56de\u4e00\u4e2a\u7ed3\u679c\uff0c\u5176\u4e2d\u5305\u542b\u4e86\u53bb\u91cd\u540e\u7684\u90e8\u95e8\u6570\u76ee\u3002<\/p>\n
          \u7efc\u4e0a\u6240\u8ff0\uff0cDISTINCT\u5173\u952e\u5b57\u5728SQL\u4e2d\u7528\u4e8e\u53bb\u9664\u67e5\u8be2\u7ed3\u679c\u4e2d\u91cd\u590d\u7684\u884c\uff0c\u975e\u5e38\u5b9e\u7528\u3002\u901a\u8fc7\u4ee5\u4e0a\u7684\u793a\u4f8b\u4ee3\u7801\uff0c\u4f60\u73b0\u5728\u5e94\u8be5\u5df2\u7ecf\u4e86\u89e3\u4e86DISTINCT\u7684\u57fa\u672c\u7528\u6cd5\uff0c\u4ee5\u53ca\u5982\u4f55\u5728\u591a\u5217\u3001\u6392\u5e8f\u548c\u8ba1\u6570\u7b49\u573a\u666f\u4e0b\u4f7f\u7528\u5b83\u3002\u5e0c\u671b\u8fd9\u7bc7\u6587\u7ae0\u80fd\u5bf9\u4f60\u5728\u5e94\u7528DISTINCT\u5173\u952e\u5b57\u65f6\u6709\u6240\u5e2e\u52a9\u3002<\/p>\n
          \u4ee5\u4e0a\u5c31\u662f\u672c\u6587\u7684\u5168\u90e8\u5185\u5bb9\u4e86\uff0c\u662f\u5426\u6709\u987a\u5229\u5e2e\u52a9\u4f60\u89e3\u51b3\u95ee\u9898\uff1f\u82e5\u662f\u80fd\u7ed9\u4f60\u5e26\u6765\u5b66\u4e60\u4e0a\u7684\u5e2e\u52a9\uff0c\u8bf7\u5927\u5bb6\u591a\u591a\u652f\u6301\u4e3b\u673a\u5b9d\u8d1d\uff01\u66f4\u591a\u5173\u4e8e\u6570\u636e\u5e93\u7684\u76f8\u5173\u77e5\u8bc6\uff0c\u4e5f\u53ef\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u3002<\/p>\n
          \n
          \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
          \u4f7f\u7528DISTINCT\u5173\u952e\u5b57\u5728SQ...<\/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-199695","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199695","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=199695"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199695\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199695"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199695"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199695"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}