{"id":199689,"date":"2025-05-06T10:46:53","date_gmt":"2025-05-06T02:46:53","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199689\/"},"modified":"2025-05-06T10:46:53","modified_gmt":"2025-05-06T02:46:53","slug":"%e4%bd%bf%e7%94%a8sql%e7%9a%84where%e6%9d%a1%e4%bb%b6%e7%ad%a1%e9%80%89%e6%95%b0%e6%8d%ae","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199689\/","title":{"rendered":"\u4f7f\u7528SQL\u7684WHERE\u6761\u4ef6\u7b61\u9009\u6570\u636e"},"content":{"rendered":"

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

\u4f7f\u7528SQL\u7684WHERE\u6761\u4ef6\u7b61\u9009\u6570\u636e<\/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\u4e2dWHERE\u7684\u7528\u6cd5\uff0c\u9700\u8981\u5177\u4f53\u4ee3\u7801\u793a\u4f8b<\/p>\n

SQL\uff08Structured Query Language\uff09\u662f\u4e00\u79cd\u7528\u4e8e\u7ba1\u7406\u5173\u7cfb\u6570\u636e\u5e93\u7ba1\u7406\u7cfb\u7edf\uff08RDBMS\uff09\u7684\u6807\u51c6\u5316\u8bed\u8a00\u3002\u5728SQL\u4e2d\uff0cWHERE\u5b50\u53e5\u7528\u4e8e\u8fc7\u6ee4SELECT\u8bed\u53e5\u8fd4\u56de\u7684\u6570\u636e\u3002\u901a\u8fc7WHERE\u5b50\u53e5\uff0c\u6211\u4eec\u53ef\u4ee5\u6839\u636e\u7279\u5b9a\u7684\u6761\u4ef6\u9009\u62e9\u9700\u8981\u7684\u6570\u636e\u884c\u3002<\/p>\n

WHERE\u5b50\u53e5\u7684\u4e00\u822c\u8bed\u6cd5\u5982\u4e0b\uff1a<\/p>\n

SELECT column1, column2, ...\nFROM table_name\nWHERE condition;<\/pre>\n
\u5728\u4e0a\u9762\u7684\u8bed\u6cd5\u4e2d\uff0ccolumn1, column2, ...<\/code>\u662f\u4f60\u60f3\u8981\u9009\u62e9\u7684\u5217\uff0ctable_name<\/code>\u662f\u4f60\u60f3\u8981\u4ece\u4e2d\u9009\u62e9\u6570\u636e\u7684\u8868\uff0ccondition<\/code>\u662f\u7b5b\u9009\u6570\u636e\u7684\u6761\u4ef6\u3002<\/p>\n
\u4e0b\u9762\u5c06\u7ed9\u51fa\u4e00\u4e9b\u5e38\u89c1\u7684\u4f8b\u5b50\u6765\u8bf4\u660eWHERE\u7684\u7528\u6cd5\u3002<\/p>\n
    \n
  1. \u7b80\u5355\u7684\u7b49\u4e8e\u64cd\u4f5c\u7b26\uff08=<\/code>\uff09\uff1a<\/li>\n<\/ol>\n
    SELECT * \nFROM customers \nWHERE city = 'New York';<\/pre>\n
    \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4ececustomers<\/code>\u8868\u4e2d\u9009\u62e9\u6240\u6709\u4f4d\u4e8e\u7ebd\u7ea6\u7684\u987e\u5ba2\u3002<\/p>\n
      \n
    1. \u4e0d\u7b49\u4e8e\u64cd\u4f5c\u7b26\uff08<><\/code>\uff09\uff1a<\/li>\n<\/ol>\n
      SELECT * \nFROM employees \nWHERE department <> 'HR';<\/pre>\n
      \u4e0a\u9762\u7684\u4ee3\u7801\u5c06\u4eceemployees<\/code>\u8868\u4e2d\u9009\u62e9\u90e8\u95e8\u4e0d\u4e3aHR\u7684\u6240\u6709\u5458\u5de5\u3002<\/p>\n
        \n
      1. \u5927\u4e8e\u64cd\u4f5c\u7b26\uff08><\/code>\uff09\uff1a<\/li>\n<\/ol>\n
        SELECT * \nFROM products \nWHERE price > 100;<\/pre>\n
        \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4eceproducts<\/code>\u8868\u4e2d\u9009\u62e9\u4ef7\u683c\u5927\u4e8e100\u7684\u6240\u6709\u4ea7\u54c1\u3002<\/p>\n
          \n
        1. \u5c0f\u4e8e\u64cd\u4f5c\u7b26\uff08<<\/code>\uff09\uff1a<\/li>\n<\/ol>\n
          SELECT * \nFROM orders \nWHERE order_date < '2021-01-01';<\/pre>\n
          \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4eceorders<\/code>\u8868\u4e2d\u9009\u62e9\u8ba2\u5355\u65e5\u671f\u65e9\u4e8e2021\u5e741\u67081\u65e5\u7684\u6240\u6709\u8ba2\u5355\u3002<\/p>\n
            \n
          1. \u5927\u4e8e\u7b49\u4e8e\u64cd\u4f5c\u7b26\uff08>=<\/code>\uff09\uff1a<\/li>\n<\/ol>\n
            SELECT * \nFROM customers \nWHERE age >= 18;<\/pre>\n
            \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4ececustomers<\/code>\u8868\u4e2d\u9009\u62e9\u5e74\u9f84\u4e0d\u5c0f\u4e8e18\u5c81\u7684\u6240\u6709\u987e\u5ba2\u3002<\/p>\n
              \n
            1. \u5c0f\u4e8e\u7b49\u4e8e\u64cd\u4f5c\u7b26\uff08<=<\/code>\uff09\uff1a<\/li>\n<\/ol>\n
              SELECT * \nFROM employees \nWHERE hire_date <= '2019-01-01';<\/pre>\n
              \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4eceemployees<\/code>\u8868\u4e2d\u9009\u62e9\u5165\u804c\u65e5\u671f\u65e9\u4e8e\u6216\u7b49\u4e8e2019\u5e741\u67081\u65e5\u7684\u6240\u6709\u5458\u5de5\u3002<\/p>\n
                \n
              1. BETWEEN\u64cd\u4f5c\u7b26\uff1a<\/li>\n<\/ol>\n
                SELECT * \nFROM products \nWHERE price BETWEEN 50 AND 100;<\/pre>\n
                \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4eceproducts<\/code>\u8868\u4e2d\u9009\u62e9\u4ef7\u683c\u572850\u548c100\u4e4b\u95f4\u7684\u6240\u6709\u4ea7\u54c1\u3002<\/p>\n
                  \n
                1. LIKE\u548c\u901a\u914d\u7b26\u64cd\u4f5c\u7b26\uff1a<\/li>\n<\/ol>\n
                  SELECT * \nFROM customers \nWHERE last_name LIKE 'Sm%';<\/pre>\n
                  \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4ececustomers<\/code>\u8868\u4e2d\u9009\u62e9\u59d3\u6c0f\u4ee5\u201cSm\u201d\u5f00\u5934\u7684\u6240\u6709\u987e\u5ba2\u3002\u901a\u914d\u7b26%<\/code>\u8868\u793a\u4efb\u610f\u5b57\u7b26\u3002<\/p>\n
                    \n
                  1. IN\u64cd\u4f5c\u7b26\uff1a<\/li>\n<\/ol>\n
                    SELECT * \nFROM employees \nWHERE department IN ('HR', 'Sales');<\/pre>\n
                    \u4e0a\u8ff0\u4ee3\u7801\u5c06\u4eceemployees<\/code>\u8868\u4e2d\u9009\u62e9\u90e8\u95e8\u4e3aHR\u6216\u9500\u552e\u7684\u6240\u6709\u5458\u5de5\u3002<\/p>\n
                    \u4ee5\u4e0a\u662f\u4e00\u4e9b\u5e38\u89c1\u7684WHERE\u5b50\u53e5\u7684\u793a\u4f8b\u4ee3\u7801\u3002\u901a\u8fc7\u8fd9\u4e9b\u793a\u4f8b\uff0c\u4f60\u53ef\u4ee5\u66f4\u597d\u5730\u7406\u89e3\u5728SQL\u67e5\u8be2\u4e2d\u4f7f\u7528WHERE\u5b50\u53e5\u7684\u7528\u6cd5\u3002\u6839\u636e\u5b9e\u9645\u9700\u6c42\uff0c\u4f60\u53ef\u4ee5\u6839\u636e\u4e0d\u540c\u7684\u6761\u4ef6\u7f16\u5199WHERE\u5b50\u53e5\uff0c\u4ee5\u83b7\u53d6\u6240\u9700\u7684\u6570\u636e\u884c\u3002<\/p>\n
                    \u6587\u4e2d\u5173\u4e8ewhere\u5b50\u53e5,where\u6761\u4ef6,SQL\u8fc7\u6ee4\u7684\u77e5\u8bc6\u4ecb\u7ecd\uff0c\u5e0c\u671b\u5bf9\u4f60\u7684\u5b66\u4e60\u6709\u6240\u5e2e\u52a9\uff01\u82e5\u662f\u53d7\u76ca\u532a\u6d45\uff0c\u90a3\u5c31\u52a8\u52a8\u9f20\u6807\u6536\u85cf\u8fd9\u7bc7\u300a\u4f7f\u7528SQL\u7684WHERE\u6761\u4ef6\u7b61\u9009\u6570\u636e\u300b\u6587\u7ae0\u5427\uff0c\u4e5f\u53ef\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u4e86\u89e3\u76f8\u5173\u6280\u672f\u6587\u7ae0\u3002<\/p>\n
                    \n
                    \n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"
                    \u4f7f\u7528SQL\u7684WHERE\u6761\u4ef6\u7b61\u9009\u6570...<\/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-199689","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199689","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=199689"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199689\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199689"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199689"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199689"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}