{"id":199704,"date":"2025-05-06T09:13:55","date_gmt":"2025-05-06T01:13:55","guid":{"rendered":"https:\/\/server.hk\/cnblog\/199704\/"},"modified":"2025-05-06T09:13:55","modified_gmt":"2025-05-06T01:13:55","slug":"mysql%e5%b0%8f%e6%95%b0%e7%b1%bb%e5%9e%8bdecimal%e7%9a%84%e4%bd%bf%e7%94%a8%e6%96%b9%e6%b3%95%e8%af%a6%e8%a7%a3","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/199704\/","title":{"rendered":"MySQL\u5c0f\u6570\u7c7b\u578bDECIMAL\u7684\u4f7f\u7528\u65b9\u6cd5\u8be6\u89e3"},"content":{"rendered":"

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

MySQL\u5c0f\u6570\u7c7b\u578bDECIMAL\u7684\u4f7f\u7528\u65b9\u6cd5\u8be6\u89e3<\/h1>\n

\u6700\u8fd1\u53d1\u73b0\u4e0d\u5c11\u5c0f\u4f19\u4f34\u90fd\u5bf9\u5f88\u611f\u5174\u8da3\uff0c\u6240\u4ee5\u4eca\u5929\u7ee7\u7eed\u7ed9\u5927\u5bb6\u4ecb\u7ecd\u76f8\u5173\u7684\u77e5\u8bc6\uff0c\u672c\u6587\u4e3b\u8981\u5185\u5bb9\u6d89\u53ca\u5230\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5e0c\u671b\u80fd\u5e2e\u5230\u4f60\uff01\u5f53\u7136\u5982\u679c\u9605\u8bfb\u672c\u6587\u65f6\u5b58\u5728\u4e0d\u540c\u60f3\u6cd5\uff0c\u53ef\u4ee5\u5728\u8bc4\u8bba\u4e2d\u8868\u8fbe\uff0c\u4f46\u662f\u8bf7\u52ff\u4f7f\u7528\u8fc7\u6fc0\u7684\u63aa\u8f9e~<\/p>\n

MySQL\u5b9a\u70b9\u6570\u7c7b\u578bDECIMAL\u7528\u6cd5\u8be6\u89e3<\/p>\n

\u5728\u6570\u636e\u5e93\u4e2d\uff0c\u7ecf\u5e38\u9700\u8981\u5904\u7406\u7cbe\u786e\u7684\u6570\u503c\uff0c\u4f8b\u5982\u8d27\u5e01\u91d1\u989d\u6216\u8005\u79d1\u5b66\u8ba1\u7b97\u7b49\u3002\u4e3a\u4e86\u4fdd\u8bc1\u8ba1\u7b97\u51c6\u786e\u6027\uff0cMySQL\u63d0\u4f9b\u4e86DECIMAL\u7c7b\u578b\uff0c\u7528\u4e8e\u5b58\u50a8\u7cbe\u786e\u7684\u5b9a\u70b9\u6570\u503c\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecdMySQL\u4e2dDECIMAL\u7c7b\u578b\u7684\u7528\u6cd5\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002<\/p>\n

\u4e00\u3001DECIMAL\u7c7b\u578b\u7684\u4ecb\u7ecd
DECIMAL\u7c7b\u578b\u662f\u4e00\u79cd\u7cbe\u786e\u6570\u503c\u7c7b\u578b\uff0c\u7528\u4e8e\u5b58\u50a8\u56fa\u5b9a\u5c0f\u6570\u4f4d\u6570\u7684\u6570\u503c\u3002\u5b83\u5177\u6709\u4ee5\u4e0b\u7279\u70b9\uff1a<\/p>\n

    \n
  1. \u5bf9\u4e8e\u5c0f\u6570\u4f4d\u6570\u56fa\u5b9a\u7684\u6570\u503c\uff0cDECIMAL\u7c7b\u578b\u53ef\u4ee5\u786e\u4fdd\u8ba1\u7b97\u7684\u7cbe\u5ea6\u548c\u51c6\u786e\u6027\u3002<\/li>\n
  2. DECIMAL\u7c7b\u578b\u53ef\u4ee5\u5b58\u50a8\u7684\u6570\u503c\u8303\u56f4\u8f83\u5927\uff0c\u6700\u5927\u53ef\u4ee5\u5b58\u50a830\u4f4d\u6570\u3002<\/li>\n
  3. DECIMAL\u7c7b\u578b\u652f\u6301\u8d1f\u6570\uff0c\u4e14\u53ef\u4ee5\u6307\u5b9a\u5c0f\u6570\u4f4d\u6570\u3002<\/li>\n<\/ol>\n

    \u4e8c\u3001DECIMAL\u7c7b\u578b\u7684\u5b9a\u4e49
    \u5728\u521b\u5efa\u8868\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528DECIMAL\u7c7b\u578b\u6765\u5b9a\u4e49\u5b57\u6bb5\u3002DECIMAL\u7684\u8bed\u6cd5\u5982\u4e0b\uff1a
    DECIMAL(M, D)<\/p>\n

    \u5176\u4e2d\uff0cM\u8868\u793a\u6570\u503c\u7684\u603b\u4f4d\u6570\uff0cD\u8868\u793a\u5c0f\u6570\u90e8\u5206\u7684\u4f4d\u6570\u3002\u4f8b\u5982\uff0cDECIMAL(10, 2)\u8868\u793a\u5141\u8bb8\u5b58\u50a8\u6700\u591a10\u4f4d\u6570\uff0c\u5176\u4e2d\u67092\u4f4d\u5c0f\u6570\u3002<\/p>\n

    \u4e09\u3001DECIMAL\u7c7b\u578b\u7684\u5e94\u7528<\/p>\n

      \n
    1. \n

      \u521b\u5efa\u8868\u5e76\u63d2\u5165\u6570\u636e
      \u4e0b\u9762\u662f\u4e00\u4e2a\u4f8b\u5b50\uff0c\u521b\u5efa\u4e00\u4e2a\u540d\u4e3aproducts\u7684\u8868\uff0c\u5e76\u5728\u8868\u4e2d\u63d2\u5165\u4e00\u4e9b\u793a\u4f8b\u6570\u636e\uff1a<\/p>\n

      CREATE TABLE products (\n id INT PRIMARY KEY AUTO_INCREMENT,\n name VARCHAR(50),\n price DECIMAL(10, 2)\n);\n \nINSERT INTO products (name, price) VALUES\n ('Product A', 10.99),\n ('Product B', 20.50),\n ('Product C', 100.75);<\/pre>\n<\/li>\n
    2. \n
      \u67e5\u8be2DECIMAL\u7c7b\u578b\u7684\u6570\u636e
      \u67e5\u8be2DECIMAL\u7c7b\u578b\u7684\u6570\u636e\u4e0e\u67e5\u8be2\u5176\u4ed6\u7c7b\u578b\u7684\u6570\u636e\u4e00\u6837\uff0c\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528SELECT\u8bed\u53e5\u67e5\u8be2products\u8868\u4e2d\u7684\u6570\u636e\uff1a<\/p>\n
      SELECT * FROM products;<\/pre>\n<\/li>\n
    3. \n
      \u4f7f\u7528DECIMAL\u7c7b\u578b\u8fdb\u884c\u8ba1\u7b97
      DECIMAL\u7c7b\u578b\u652f\u6301\u52a0\u51cf\u4e58\u9664\u7b49\u57fa\u672c\u7684\u6570\u5b66\u8ba1\u7b97\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u8ba1\u7b97\u6240\u6709\u4ea7\u54c1\u4ef7\u683c\u7684\u603b\u548c\uff1a<\/p>\n
      SELECT SUM(price) FROM products;<\/pre>\n<\/li>\n
    4. \n
      \u66f4\u65b0DECIMAL\u7c7b\u578b\u7684\u6570\u636e
      \u66f4\u65b0DECIMAL\u7c7b\u578b\u7684\u6570\u636e\u4e0e\u66f4\u65b0\u5176\u4ed6\u7c7b\u578b\u7684\u6570\u636e\u4e00\u6837\uff0c\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528UPDATE\u8bed\u53e5\u66f4\u65b0\u4ef7\u683c\u4e3a20.50\u7684\u4ea7\u54c1\u4ef7\u683c\uff1a<\/p>\n
      UPDATE products SET price = 30.00 WHERE price = 20.50;<\/pre>\n<\/li>\n
    5. \n
      \u5220\u9664DECIMAL\u7c7b\u578b\u7684\u6570\u636e
      \u5220\u9664DECIMAL\u7c7b\u578b\u7684\u6570\u636e\u4e0e\u5220\u9664\u5176\u4ed6\u7c7b\u578b\u7684\u6570\u636e\u4e00\u6837\uff0c\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528DELETE\u8bed\u53e5\u5220\u9664\u4ef7\u683c\u5927\u4e8e\u7b49\u4e8e100\u7684\u4ea7\u54c1\uff1a<\/p>\n
      DELETE FROM products WHERE price >= 100.00;<\/pre>\n<\/li>\n<\/ol>\n
      \u56db\u3001\u603b\u7ed3
      \u672c\u6587\u4ecb\u7ecd\u4e86MySQL\u4e2dDECIMAL\u7c7b\u578b\u7684\u7528\u6cd5\uff0c\u5e76\u63d0\u4f9b\u4e86\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002\u4f7f\u7528DECIMAL\u7c7b\u578b\u53ef\u4ee5\u786e\u4fdd\u7cbe\u786e\u7684\u8ba1\u7b97\u548c\u5b58\u50a8\u5b9a\u70b9\u6570\u503c\uff0c\u7279\u522b\u9002\u7528\u4e8e\u9700\u8981\u5904\u7406\u8d27\u5e01\u91d1\u989d\u6216\u79d1\u5b66\u8ba1\u7b97\u7684\u573a\u666f\u3002\u5728\u521b\u5efa\u8868\u65f6\uff0c\u53ef\u4ee5\u6839\u636e\u9700\u8981\u5b9a\u4e49\u6570\u503c\u7684\u603b\u4f4d\u6570\u548c\u5c0f\u6570\u4f4d\u6570\u3002\u4f7f\u7528DECIMAL\u7c7b\u578b\u8fdb\u884c\u67e5\u8be2\u3001\u8ba1\u7b97\u548c\u66f4\u65b0\u7b49\u64cd\u4f5c\u4e0e\u5176\u4ed6\u6570\u636e\u7c7b\u578b\u57fa\u672c\u76f8\u540c\u3002<\/p>\n
      \u53c2\u8003\u8d44\u6599\uff1a<\/p>\n
        \n
      • MySQL\u5b98\u65b9\u6587\u6863\uff1ahttps:\/\/dev.mysql.com\/doc\/refman\/8.0\/en\/precision-math-decimal-characteristics.html<\/li>\n<\/ul>\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":"
        MySQL\u5c0f\u6570\u7c7b\u578bDECIMAL...<\/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-199704","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199704","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=199704"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/199704\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=199704"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=199704"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=199704"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}