{"id":187234,"date":"2024-11-11T12:34:20","date_gmt":"2024-11-11T04:34:20","guid":{"rendered":"https:\/\/server.hk\/cnblog\/187234\/"},"modified":"2024-11-11T12:34:21","modified_gmt":"2024-11-11T04:34:21","slug":"%e6%95%b8%e6%93%9a%e5%ba%ab%e4%b8%a8%e5%be%9emysql%e6%95%b8%e5%80%bc%e9%9a%b1%e5%bc%8f%e8%bd%89%e6%8f%9b%e6%88%90%e4%ba%86double%e5%9e%8b%e7%9a%84%e6%b8%ac%e8%a9%a6%e9%bb%9e%ef%bc%8c%e5%80%bc%e5%be%97","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/187234\/","title":{"rendered":"\u6578\u64da\u5eab\u4e28\u5f9eMySQL\u6578\u503c\u96b1\u5f0f\u8f49\u63db\u6210\u4e86double\u578b\u7684\u6e2c\u8a66\u9ede\uff0c\u503c\u5f97\u5b78\u7fd2"},"content":{"rendered":"<h1 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id=\"%e9%9a%b1%e5%bc%8f%e8%bd%89%e6%8f%9b%e7%9a%84%e6%a6%82%e5%bf%b5-ktakeTfLLx\">\u96b1\u5f0f\u8f49\u63db\u7684\u6982\u5ff5<\/h2>\n<p>\u96b1\u5f0f\u8f49\u63db\u662f\u6307\u5728\u8868\u9054\u5f0f\u4e2d\uff0cMySQL\u81ea\u52d5\u5c07\u4e00\u7a2e\u6578\u64da\u985e\u578b\u8f49\u63db\u70ba\u53e6\u4e00\u7a2e\u6578\u64da\u985e\u578b\u7684\u904e\u7a0b\u3002\u4f8b\u5982\uff0c\u7576\u4e00\u500b\u6574\u6578\u8207\u4e00\u500b\u6d6e\u9ede\u6578\u9032\u884c\u904b\u7b97\u6642\uff0c\u6574\u6578\u6703\u88ab\u81ea\u52d5\u8f49\u63db\u70ba\u6d6e\u9ede\u6578\uff0c\u4ee5\u4fbf\u9032\u884c\u6b63\u78ba\u7684\u8a08\u7b97\u3002<\/p>\n<h2 id=\"%e5%be%9e%e6%95%b4%e6%95%b8%e5%88%b0double%e7%9a%84%e9%9a%b1%e5%bc%8f%e8%bd%89%e6%8f%9b-ktakeTfLLx\">\u5f9e\u6574\u6578\u5230double\u7684\u96b1\u5f0f\u8f49\u63db<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u7576\u6574\u6578\u8207\u6d6e\u9ede\u6578\u9032\u884c\u904b\u7b97\u6642\uff0c\u6574\u6578\u6703\u88ab\u96b1\u5f0f\u8f49\u63db\u70badouble\u578b\u3002\u9019\u4e00\u904e\u7a0b\u7684\u5177\u9ad4\u884c\u70ba\u53ef\u4ee5\u901a\u904e\u4ee5\u4e0b\u793a\u4f8b\u4f86\u8aaa\u660e\uff1a<\/p>\n<pre><code>SELECT 5 + 2.5;  -- \u7d50\u679c\u70ba 7.5\uff0c\u6574\u65785\u88ab\u8f49\u63db\u70badouble\u578b\nSELECT 10 * 3.14; -- \u7d50\u679c\u70ba 31.4\uff0c\u6574\u657810\u88ab\u8f49\u63db\u70badouble\u578b\n<\/code><\/pre>\n<p>\u5728\u9019\u4e9b\u4f8b\u5b50\u4e2d\uff0c\u6574\u6578\u5728\u904b\u7b97\u904e\u7a0b\u4e2d\u88ab\u81ea\u52d5\u8f49\u63db\u70badouble\u578b\uff0c\u9019\u6a23\u53ef\u4ee5\u4fdd\u8b49\u8a08\u7b97\u7684\u7cbe\u78ba\u6027\u3002<\/p>\n<h2 id=\"%e6%b8%ac%e8%a9%a6%e9%bb%9e%ef%bc%9a%e9%9a%b1%e5%bc%8f%e8%bd%89%e6%8f%9b%e7%9a%84%e5%bd%b1%e9%9f%bf-ktakeTfLLx\">\u6e2c\u8a66\u9ede\uff1a\u96b1\u5f0f\u8f49\u63db\u7684\u5f71\u97ff<\/h2>\n<p>\u5728\u5be6\u969b\u958b\u767c\u4e2d\uff0c\u96b1\u5f0f\u8f49\u63db\u53ef\u80fd\u6703\u5c0e\u81f4\u4e00\u4e9b\u6f5b\u5728\u7684\u554f\u984c\uff0c\u7279\u5225\u662f\u5728\u6578\u64da\u6bd4\u8f03\u548c\u689d\u4ef6\u7be9\u9078\u6642\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u6e2c\u8a66\u9ede\uff0c\u958b\u767c\u8005\u61c9\u8a72\u7279\u5225\u6ce8\u610f\uff1a<\/p>\n<ul>\n<li><strong>\u6bd4\u8f03\u64cd\u4f5c\uff1a<\/strong>\u7576\u6574\u6578\u8207\u6d6e\u9ede\u6578\u9032\u884c\u6bd4\u8f03\u6642\uff0c\u6574\u6578\u6703\u88ab\u8f49\u63db\u70ba\u6d6e\u9ede\u6578\uff0c\u9019\u53ef\u80fd\u6703\u5f71\u97ff\u6bd4\u8f03\u7d50\u679c\u3002<\/li>\n<li><strong>\u6578\u64da\u63d2\u5165\uff1a<\/strong>\u5728\u63d2\u5165\u6578\u64da\u6642\uff0c\u5982\u679c\u6578\u64da\u985e\u578b\u4e0d\u5339\u914d\uff0cMySQL\u6703\u81ea\u52d5\u9032\u884c\u8f49\u63db\uff0c\u9019\u53ef\u80fd\u5c0e\u81f4\u6578\u64da\u7cbe\u5ea6\u7684\u640d\u5931\u3002<\/li>\n<li><strong>\u6027\u80fd\u5f71\u97ff\uff1a<\/strong>\u96b1\u5f0f\u8f49\u63db\u53ef\u80fd\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u5927\u578b\u6578\u64da\u96c6\u4e0a\u9032\u884c\u8a08\u7b97\u6642\u3002<\/li>\n<\/ul>\n<h2 id=\"%e6%9c%80%e4%bd%b3%e5%af%a6%e8%b8%90-ktakeTfLLx\">\u6700\u4f73\u5be6\u8e10<\/h2>\n<p>\u70ba\u4e86\u907f\u514d\u96b1\u5f0f\u8f49\u63db\u5e36\u4f86\u7684\u554f\u984c\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u9075\u5faa\u4ee5\u4e0b\u6700\u4f73\u5be6\u8e10\uff1a<\/p>\n<ul>\n<li><strong>\u660e\u78ba\u6578\u64da\u985e\u578b\uff1a<\/strong>\u5728\u9032\u884c\u6578\u64da\u64cd\u4f5c\u6642\uff0c\u76e1\u91cf\u4f7f\u7528\u660e\u78ba\u7684\u6578\u64da\u985e\u578b\uff0c\u907f\u514d\u4f9d\u8cf4\u96b1\u5f0f\u8f49\u63db\u3002<\/li>\n<li><strong>\u4f7f\u7528CAST\u51fd\u6578\uff1a<\/strong>\u5728\u9700\u8981\u9032\u884c\u985e\u578b\u8f49\u63db\u6642\uff0c\u4f7f\u7528CAST\u6216CONVERT\u51fd\u6578\u4f86\u660e\u78ba\u6307\u5b9a\u8f49\u63db\u985e\u578b\u3002<\/li>\n<li><strong>\u6e2c\u8a66\u548c\u9a57\u8b49\uff1a<\/strong>\u5728\u958b\u767c\u904e\u7a0b\u4e2d\uff0c\u5c0d\u6578\u64da\u64cd\u4f5c\u9032\u884c\u5145\u5206\u7684\u6e2c\u8a66\uff0c\u78ba\u4fdd\u7d50\u679c\u7b26\u5408\u9810\u671f\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b5%90%e8%ab%96-ktakeTfLLx\">\u7d50\u8ad6<\/h2>\n<p>MySQL\u4e2d\u7684\u6578\u503c\u96b1\u5f0f\u8f49\u63db\u662f\u4e00\u500b\u91cd\u8981\u7684\u6982\u5ff5\uff0c\u7406\u89e3\u5176\u904b\u4f5c\u65b9\u5f0f\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u907f\u514d\u6f5b\u5728\u7684\u554f\u984c\u3002\u5728\u9032\u884c\u6578\u64da\u64cd\u4f5c\u6642\uff0c\u958b\u767c\u8005\u61c9\u8a72\u6ce8\u610f\u6578\u64da\u985e\u578b\u7684\u9078\u64c7\u548c\u8f49\u63db\uff0c\u4e26\u9075\u5faa\u6700\u4f73\u5be6\u8e10\u4f86\u78ba\u4fdd\u6578\u64da\u7684\u6e96\u78ba\u6027\u548c\u6027\u80fd\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u7684\u5ba2\u6236\u3002\u7121\u8ad6\u662f <a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a> \u9084\u662f\u5176\u4ed6\u670d\u52d9\uff0c\u6211\u5011\u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u53ef\u9760\u7684\u652f\u6301\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u63a2\u7d22MySQL\u4e2d\u6578\u503c\u96b1\u5f0f\u8f49\u63db\u70badouble\u578b\u7684\u6e2c\u8a66\u9ede\uff0c\u6df1\u5165\u7406\u89e3\u6578\u64da\u5eab\u64cd\u4f5c\u7684\u95dc\u9375\u6982\u5ff5\uff0c\u63d0\u5347\u4f60\u7684\u6280\u8853\u80fd\u529b\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-187234","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187234","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=187234"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187234\/revisions"}],"predecessor-version":[{"id":187235,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/187234\/revisions\/187235"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=187234"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=187234"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=187234"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}