{"id":959,"date":"2025-10-24T14:55:16","date_gmt":"2025-10-24T06:55:16","guid":{"rendered":"https:\/\/www.ikaros.love\/?p=959"},"modified":"2025-10-24T14:55:16","modified_gmt":"2025-10-24T06:55:16","slug":"mysql-float-%e7%9a%84%e9%bb%98%e8%ae%a4%e7%b2%be%e5%ba%a6%e4%b8%8e%e9%87%91%e9%a2%9d%e5%ad%98%e5%82%a8%e7%9a%84%e6%9c%80%e4%bd%b3%e5%ae%9e%e8%b7%b5","status":"publish","type":"post","link":"https:\/\/www.ikaros.love\/?p=959","title":{"rendered":"MySQL FLOAT \u7684\u9ed8\u8ba4\u7cbe\u5ea6\u4e0e\u91d1\u989d\u5b58\u50a8\u7684\u6700\u4f73\u5b9e\u8df5"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

\u5728\u5e94\u7528\u5f00\u53d1\u4e2d\uff0c\u5c24\u5176\u662f\u5728\u5904\u7406\u91d1\u989d\u6570\u636e\u65f6\uff0c\u4f7f\u7528\u6d6e\u70b9\u6570\uff08\u5982 Java \u7684 Float<\/code> \u5bf9\u5e94 MySQL \u7684 FLOAT<\/code>\uff09\u662f\u4e00\u4e2a\u5e38\u89c1\u7684\u8bef\u533a\u3002\u672c\u6587\u5c06\u6df1\u5165\u5206\u6790\u4e00\u4e2a\u5b9e\u9645\u6848\u4f8b\uff1a\u6570\u636e\u5728 Java \u5e94\u7528\u5c42\u5177\u6709\u5c0f\u6570\u7cbe\u5ea6\uff0c\u4f46\u5b58\u50a8\u5230 MySQL \u4e2d\u5374\u8be1\u5f02\u5730\u88ab\u622a\u65ad\u5230\u4e2a\u4f4d\u3002<\/p>\n\n\n\n

\u95ee\u9898\u63cf\u8ff0\uff1a\u6d6e\u70b9\u6570\u7684\u7cbe\u5ea6\u53bb\u54ea\u4e86\uff1f<\/h2>\n\n\n\n

\u5728\u4e00\u4e2a\u5904\u7406\u85aa\u8d44\u6570\u636e\u7684\u6a21\u5757\u4e2d\uff0c\u6211\u4eec\u89c2\u5bdf\u5230\u4e00\u4e2a\u53cd\u5e38\u73b0\u8c61\uff1a<\/p>\n\n\n\n

    \n
  1. \u6570\u636e\u7c7b\u578b\u5b9a\u4e49<\/strong>\uff1aMySQL \u8868\u5b57\u6bb5\u88ab\u5b9a\u4e49\u4e3a\u6807\u51c6\u7684 FLOAT<\/code> \u7c7b\u578b\uff08\u672a\u6307\u5b9a\u7cbe\u5ea6\uff0c\u5982 FLOAT(10, 2)<\/code>\uff09\u3002<\/li>\n\n\n\n
  2. \u5e94\u7528\u5c42\u72b6\u6001<\/strong>\uff1aJava \u540e\u7aef\u4f7f\u7528 Float<\/code> \u7c7b\u578b\u5b58\u50a8\u65e5\u5de5\u8d44\/\u6708\u5de5\u8d44\uff0c\u5e76\u901a\u8fc7 Mybatis \u4f20\u9012\u5230\u6570\u636e\u5e93\u3002\u901a\u8fc7\u65e5\u5fd7\u548c\u65ad\u70b9\u786e\u8ba4\uff0c\u5728 SQL \u6267\u884c\u4e4b\u524d\uff0c\u6570\u503c\uff08\u4f8b\u5982 141707.8<\/code>\uff09\u662f\u6b63\u786e\u7684\u6d6e\u70b9\u6570\u3002<\/li>\n\n\n\n
  3. \u7ed3\u679c<\/strong>\uff1a\u76f4\u63a5\u67e5\u8be2\u6570\u636e\u5e93\uff0c\u53d1\u73b0\u5b58\u50a8\u7684\u503c\u88ab\u9650\u5236\u5230\u4e2a\u4f4d\uff08\u4f8b\u5982 141707.8<\/code> \u53d8\u6210\u4e86 141707<\/code> \u6216 141708<\/code>\uff09\uff0c\u5c0f\u6570\u90e8\u5206\u5b8c\u5168\u4e22\u5931\u3002<\/li>\n<\/ol>\n\n\n\n

    \u6838\u5fc3\u77db\u76fe\uff1a<\/strong> \u4e3a\u4ec0\u4e48\u4e00\u4e2a\u8bbe\u8ba1\u4e0a\u652f\u6301\u5c0f\u6570\u7684 FLOAT<\/code> \u5b57\u6bb5\uff0c\u4f1a\u65e0\u6545\u5c06\u4f20\u5165\u7684\u5c0f\u6570\u90e8\u5206\u622a\u65ad\uff1f<\/p>\n\n\n\n

    \n\n\n\n

    \ud83d\udee0\ufe0f \u89e3\u51b3\u601d\u8def\u4e0e\u539f\u7406\u89e3\u6790<\/h2>\n\n\n\n

    \u901a\u8fc7\u5168\u94fe\u8def\u6392\u67e5\uff0c\u6211\u4eec\u6392\u9664\u4e86 Java \u5b9e\u4f53\u7c7b\u7c7b\u578b\u9519\u8bef\u3001\u5e94\u7528\u7a0b\u5e8f\u4ee3\u7801\u622a\u65ad\u7b49\u5e38\u89c1\u95ee\u9898\uff0c\u6700\u7ec8\u5c06\u76ee\u6807\u9501\u5b9a\u5728 MySQL \u7684 FLOAT<\/code> \u5b57\u6bb5\u5b9a\u4e49<\/strong>\u4e0a\u3002<\/p>\n\n\n\n

    \u6839\u6e90\u5206\u6790\uff1aMySQL FLOAT \u7684\u9ed8\u8ba4\u884c\u4e3a\u9677\u9631<\/h3>\n\n\n\n

    \u6807\u51c6\u7684 FLOAT<\/code> \u7c7b\u578b\u5728 MySQL \u4e2d\u9ed8\u8ba4\u662f 4 \u5b57\u8282\u7684\u5355\u7cbe\u5ea6\u6d6e\u70b9\u6570\u3002\u5f53\u6211\u4eec\u4f7f\u7528 FLOAT<\/code><\/strong> \uff08\u4e0d\u5e26 M, D \u53c2\u6570\uff09<\/strong> \u5b9a\u4e49\u5b57\u6bb5\u65f6\uff0c\u76f8\u5f53\u4e8e\u8ba9 MySQL \u4f7f\u7528\u5176\u5185\u90e8\u7684\u9ed8\u8ba4\u6d6e\u70b9\u6570\u5b58\u50a8\u903b\u8f91\u3002<\/p>\n\n\n\n

    \u5728\u67d0\u4e9b\u7279\u5b9a\u7684 MySQL \u7248\u672c\u6216\u914d\u7f6e\u4e0b\uff0c\u5f53\u6570\u636e\u901a\u8fc7 JDBC \u9a71\u52a8\u5199\u5165\u6ca1\u6709\u663e\u5f0f\u7cbe\u5ea6\u7ea6\u675f<\/strong>\u7684 FLOAT<\/code> \u5b57\u6bb5\u65f6\uff0c\u6570\u636e\u5e93\u53ef\u80fd\u4f1a\u91c7\u7528\u4e00\u79cd\u4fdd\u5b88\u6216\u4e0d\u517c\u5bb9\u7684\u5b58\u50a8\/\u663e\u793a\u673a\u5236\uff0c\u5bfc\u81f4\u5b83**\u622a\u65ad\uff08\u6216\u663e\u793a\u4e3a\u622a\u65ad\uff09**\u5c0f\u6570\u90e8\u5206\uff0c\u5c24\u5176\u662f\u5728\u4e0e Java Float<\/code> \u4ea4\u4e92\u65f6\u3002<\/p>\n\n\n\n

    \u4e34\u65f6\u7684\u6280\u672f\u89e3\u6cd5\uff1a\u663e\u5f0f\u6307\u5b9a\u7cbe\u5ea6 FLOAT(M, D)<\/code><\/h3>\n\n\n\n

    \u89e3\u51b3\u8fd9\u4e00\u95ee\u9898\u7684\u76f4\u63a5\u65b9\u6cd5\u662f\u6253\u7834\u8fd9\u79cd\u9ed8\u8ba4\u884c\u4e3a<\/strong>\uff0c\u901a\u8fc7\u5728\u5b57\u6bb5\u5b9a\u4e49\u65f6\u663e\u5f0f\u6307\u5b9a\u603b\u4f4d\u6570\uff08M\uff09\u548c\u5c0f\u6570\u4f4d\u6570\uff08D\uff09<\/strong>\uff0c\u5f3a\u5236 MySQL \u6309\u7167\u9884\u671f\u7684\u7cbe\u5ea6\u5b58\u50a8\u6570\u636e\u3002<\/p>\n\n\n\n

    SQL \u4fee\u590d\u8bed\u53e5\u793a\u4f8b\uff1a<\/strong><\/p>\n\n\n\n

    SQL<\/p>\n\n\n\n

    ALTER TABLE cost_of_lost_labour_data\nMODIFY COLUMN list_of_proof_of_income_flow_daily_wages FLOAT(10, 2) NOT NULL COMMENT '\u5de5\u8d44\u8bc1\u660e\u65e5\u5de5\u8d44';\n<\/code><\/pre>\n\n\n\n
    \u5f53\u5b9a\u4e49\u4e3a FLOAT(10, 2)<\/code> \u540e\uff1a<\/p>\n\n\n\n
      \n
    1. \u5f3a\u5236\u7cbe\u5ea6\uff1a<\/strong> MySQL \u88ab\u544a\u77e5\u8be5\u5b57\u6bb5\u9700\u8981\u4fdd\u7559\u5c0f\u6570\u70b9\u540e\u4e24\u4f4d\u3002<\/li>\n\n\n\n
    2. \u56db\u820d\u4e94\u5165\uff1a<\/strong> \u6570\u636e\u5e93\u5c06\u5bf9\u4f20\u5165\u7684\u503c\u8fdb\u884c\u56db\u820d\u4e94\u5165\u5230 2 \u4f4d\u5c0f\u6570\uff0c\u800c\u4e0d\u662f\u7c97\u66b4\u5730\u622a\u65ad\u5230\u4e2a\u4f4d\u3002<\/li>\n<\/ol>\n\n\n\n
      \u5b9e\u9a8c\u8bc1\u660e\uff0c\u8fd9\u4e00\u6539\u52a8\u6210\u529f\u89e3\u51b3\u4e86\u5c0f\u6570\u88ab\u9650\u5236\u5230\u4e2a\u4f4d\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n
      \n\n\n\n
      \ud83d\udca1 \u7ec8\u6781\u5fe0\u544a\uff1a\u91d1\u989d\u5b58\u50a8\u7684\u884c\u4e1a\u6700\u4f73\u5b9e\u8df5<\/h2>\n\n\n\n
      \u867d\u7136 FLOAT(10, 2)<\/code> \u89e3\u51b3\u4e86\u5f53\u524d\u7684 Bug\uff0c\u4f46\u5bf9\u4e8e\u91d1\u989d\u6216\u4efb\u4f55\u9700\u8981\u9ad8\u7cbe\u786e\u5ea6\u7684\u6570\u503c<\/strong>\uff0c\u4e1a\u754c\u5f3a\u70c8\u4e0d\u5efa\u8bae\u4f7f\u7528\u4efb\u4f55\u6d6e\u70b9\u6570\u7c7b\u578b\uff08FLOAT<\/code> \u6216 DOUBLE<\/code>\uff09<\/strong>\u3002<\/p>\n\n\n\n
      \u4e3a\u4ec0\u4e48\u4e0d\u80fd\u7528 FLOAT<\/code>\/DOUBLE<\/code>\uff1f<\/h3>\n\n\n\n
      FLOAT<\/code> \u548c DOUBLE<\/code> \u662f\u8fd1\u4f3c\u6570\u503c\u7c7b\u578b<\/strong>\uff0c\u5b83\u4eec\u4f7f\u7528\u4e8c\u8fdb\u5236\u6d6e\u70b9\u8868\u793a\u6cd5\uff08IEEE 754 \u6807\u51c6\uff09\uff0c\u65e0\u6cd5\u7cbe\u786e\u8868\u793a\u6240\u6709\u5341\u8fdb\u5236\u5c0f\u6570\uff08\u4f8b\u5982 0.1<\/code> \u5728\u4e8c\u8fdb\u5236\u4e2d\u662f\u65e0\u9650\u5faa\u73af\u5c0f\u6570\uff09\u3002<\/p>\n\n\n\n
      \u8fd9\u4f1a\u5bfc\u81f4\u8ba1\u7b97\u7ed3\u679c\u51fa\u73b0\u5fae\u5c0f\u7684\u820d\u5165\u8bef\u5dee\uff0c\u4f8b\u5982\uff1a10.20 + 20.30<\/code> \u6700\u7ec8\u53ef\u80fd\u5b58\u50a8\u6216\u8ba1\u7b97\u4e3a 30.500000000000004<\/code>\u3002\u5728\u8d22\u52a1\u548c\u4f1a\u8ba1\u9886\u57df\uff0c\u4efb\u4f55\u5fae\u5c0f\u7684\u8bef\u5dee\u90fd\u662f\u4e0d\u53ef\u63a5\u53d7\u7684\u3002<\/p>\n\n\n\n
      \u6700\u4f73\u5b9e\u8df5\uff1a\u4f7f\u7528 DECIMAL<\/code> \u548c BigDecimal<\/code><\/h3>\n\n\n\n
      \u5bf9\u4e8e\u91d1\u989d\u6570\u636e\uff0c\u5e94\u9075\u5faa\u4ee5\u4e0b\u9ec4\u91d1\u6807\u51c6\uff1a<\/p>\n\n\n\n
      \u7ec4\u4ef6<\/strong><\/td>\u6570\u636e\u7c7b\u578b<\/strong><\/td>\u4f5c\u7528<\/strong><\/td><\/tr><\/thead>
      \u6570\u636e\u5e93<\/strong><\/td>DECIMAL(M, D)<\/code><\/strong><\/td>\u7cbe\u786e\u6570\u503c\u7c7b\u578b (Exact Numeric Data Type)<\/strong>\u3002\u4ee5\u5b57\u7b26\u4e32\u5f62\u5f0f\u5b58\u50a8\uff0c\u4fdd\u8bc1\u5b8c\u5168\u7cbe\u786e\uff0c\u65e0\u7cbe\u5ea6\u635f\u5931\u3002\u63a8\u8350\u683c\u5f0f\u5982 DECIMAL(10, 2)<\/code> \u6216 DECIMAL(13, 4)<\/code>\u3002<\/td><\/tr>
      Java \u5e94\u7528<\/strong><\/td>java.math.BigDecimal<\/code><\/strong><\/td>\u5bf9\u5e94 DECIMAL<\/code>\uff0c\u63d0\u4f9b\u7cbe\u786e\u7684\u5341\u8fdb\u5236\u8fd0\u7b97\u80fd\u529b\uff0c\u907f\u514d Java \u8bed\u8a00\u4e2d Float<\/code>\/Double<\/code> \u7684\u8ba1\u7b97\u8bef\u5dee\u3002<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
      \n\n\n\n
      \ud83d\udcdd \u95ee\u9898\u603b\u7ed3\u4e0e\u7ecf\u9a8c\u63d0\u70bc<\/h2>\n\n\n\n
      \u672c\u6b21\u6392\u67e5\u66b4\u9732\u4e86\u4e24\u4e2a\u6838\u5fc3\u95ee\u9898\uff1a<\/p>\n\n\n\n
        \n
      1. MySQL \u9677\u9631\uff1a<\/strong> \u5728 MySQL \u4e2d\u5b9a\u4e49 FLOAT<\/code> \u5b57\u6bb5\u65f6\uff0c\u5982\u679c\u672a\u6307\u5b9a (M, D)<\/code> \u7cbe\u5ea6\uff0c\u53ef\u80fd\u89e6\u53d1\u9690\u5f0f\u7684\u3001\u4e0d\u9884\u671f\u7684\u5c0f\u6570\u622a\u65ad<\/strong>\u884c\u4e3a\u3002<\/li>\n\n\n\n
      2. \u6280\u672f\u9009\u578b\u9519\u8bef\uff1a<\/strong> \u91d1\u989d\u6570\u636e\u662f\u5178\u578b\u7684\u7cbe\u786e\u503c<\/strong>\uff0c\u4f7f\u7528\u6d6e\u70b9\u6570 (FLOAT<\/code>\/DOUBLE<\/code>) \u4ece\u6839\u672c\u4e0a\u5c31\u5f15\u5165\u4e86\u7cbe\u5ea6\u98ce\u9669\u3002<\/li>\n<\/ol>\n\n\n\n
        \u6700\u7ec8\u5efa\u8bae\uff1a<\/strong><\/p>\n\n\n\n
        \u5bf9\u4e8e\u6240\u6709\u6d89\u53ca\u91d1\u94b1\u3001\u5e93\u5b58\u6216\u4efb\u4f55\u9700\u8981\u7edd\u5bf9\u7cbe\u786e\u5ea6\u7684\u6570\u5b57\uff0c\u8bf7\u7acb\u5373<\/strong>\u5207\u6362\u6570\u636e\u7c7b\u578b\uff1a\u6570\u636e\u5e93\u4f7f\u7528 DECIMAL<\/code>\uff0c\u5e94\u7528\u5c42\u4f7f\u7528 BigDecimal<\/code><\/strong>\u3002\u5c06 FLOAT<\/code> \u4ec5\u4fdd\u7559\u7ed9\u90a3\u4e9b\u53ef\u4ee5\u63a5\u53d7\u5c11\u91cf\u8bef\u5dee\u7684\u79d1\u5b66\u8ba1\u7b97\u6216\u7edf\u8ba1\u6570\u636e\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
        \u5728\u5e94\u7528\u5f00\u53d1\u4e2d\uff0c\u5c24\u5176\u662f\u5728\u5904\u7406\u91d1\u989d\u6570...<\/p>\n","protected":false},"author":1,"featured_media":960,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[255,221,254,257,256],"_links":{"self":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts\/959"}],"collection":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=959"}],"version-history":[{"count":1,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts\/959\/revisions"}],"predecessor-version":[{"id":961,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/posts\/959\/revisions\/961"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=\/wp\/v2\/media\/960"}],"wp:attachment":[{"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=959"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=959"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ikaros.love\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=959"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}