{"id":79544,"date":"2024-10-16T13:11:17","date_gmt":"2024-10-16T05:11:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/79544\/"},"modified":"2024-10-16T13:11:18","modified_gmt":"2024-10-16T05:11:18","slug":"mysql%e6%8c%87%e4%bb%a4-real%ef%bc%88%e5%af%a6%e6%95%b8%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/79544\/","title":{"rendered":"MySQL\u6307\u4ee4: REAL\uff08\u5be6\u6578\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-real%ef%bc%88%e5%af%a6%e6%95%b8%ef%bc%89-hQuvlegRdW\">MySQL\u6307\u4ee4: REAL\uff08\u5be6\u6578\uff09<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u95dc\u806f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u652f\u6301\u591a\u7a2e\u6578\u64da\u985e\u578b\uff0c\u5176\u4e2d\u4e4b\u4e00\u5c31\u662fREAL\uff08\u5be6\u6578\uff09\u3002\u5728\u672c\u6587\u4e2d\uff0c\u6211\u5011\u5c07\u6df1\u5165\u63a2\u8a0eMySQL\u4e2d\u7684REAL\u6578\u64da\u985e\u578b\uff0c\u5305\u62ec\u5176\u7279\u6027\u3001\u4f7f\u7528\u5834\u666f\u4ee5\u53ca\u5982\u4f55\u5728\u5be6\u969b\u61c9\u7528\u4e2d\u9032\u884c\u64cd\u4f5c\u3002<\/p>\n<h2 id=\"real%e6%95%b8%e6%93%9a%e9%a1%9e%e5%9e%8b%e6%a6%82%e8%bf%b0-hQuvlegRdW\">REAL\u6578\u64da\u985e\u578b\u6982\u8ff0<\/h2>\n<p>REAL\u6578\u64da\u985e\u578b\u7528\u65bc\u5b58\u5132\u6d6e\u9ede\u6578\uff0c\u9019\u4e9b\u6578\u5b57\u53ef\u4ee5\u5305\u542b\u5c0f\u6578\u90e8\u5206\u3002\u6839\u64daIEEE 754\u6a19\u6e96\uff0cREAL\u901a\u5e38\u8868\u793a\u70ba\u55ae\u7cbe\u5ea6\u6d6e\u9ede\u6578\uff0c\u9019\u610f\u5473\u8457\u5b83\u53ef\u4ee5\u63d0\u4f9b\u5927\u7d047\u4f4d\u5341\u9032\u5236\u6578\u7684\u7cbe\u5ea6\u3002\u9019\u4f7f\u5f97REAL\u975e\u5e38\u9069\u5408\u9700\u8981\u9032\u884c\u6578\u5b78\u8a08\u7b97\u7684\u61c9\u7528\u5834\u666f\u3002<\/p>\n<h2 id=\"real%e8%88%87float%e7%9a%84%e5%8d%80%e5%88%a5-hQuvlegRdW\">REAL\u8207FLOAT\u7684\u5340\u5225<\/h2>\n<p>\u5728MySQL\u4e2d\uff0cREAL\u548cFLOAT\u90fd\u662f\u7528\u4f86\u5b58\u5132\u6d6e\u9ede\u6578\u7684\u6578\u64da\u985e\u578b\uff0c\u4f46\u5b83\u5011\u4e4b\u9593\u6709\u4e00\u4e9b\u7d30\u5fae\u7684\u5dee\u5225\uff1a<\/p>\n<ul>\n<li><strong>\u7cbe\u5ea6\uff1a<\/strong>REAL\u901a\u5e38\u63d0\u4f9b\u55ae\u7cbe\u5ea6\uff0c\u800cFLOAT\u53ef\u4ee5\u662f\u55ae\u7cbe\u5ea6\u6216\u96d9\u7cbe\u5ea6\uff0c\u5177\u9ad4\u53d6\u6c7a\u65bc\u5b9a\u7fa9\u6642\u7684\u53c3\u6578\u3002<\/li>\n<li><strong>\u5b58\u5132\u7a7a\u9593\uff1a<\/strong>REAL\u4f54\u75284\u500b\u5b57\u7bc0\uff0c\u800cFLOAT\u7684\u5b58\u5132\u7a7a\u9593\u5247\u53d6\u6c7a\u65bc\u5176\u7cbe\u5ea6\u8a2d\u5b9a\uff0c\u53ef\u80fd\u662f4\u62168\u500b\u5b57\u7bc0\u3002<\/li>\n<\/ul>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8real%e6%95%b8%e6%93%9a%e9%a1%9e%e5%9e%8b-hQuvlegRdW\">\u5982\u4f55\u4f7f\u7528REAL\u6578\u64da\u985e\u578b<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u4f7f\u7528REAL\u6578\u64da\u985e\u578b\u975e\u5e38\u7c21\u55ae\u3002\u4ee5\u4e0b\u662f\u5275\u5efa\u4e00\u500b\u5305\u542bREAL\u985e\u578b\u5b57\u6bb5\u7684\u8868\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>CREATE TABLE products (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    name VARCHAR(100),\n    price REAL\n);<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u6211\u5011\u5275\u5efa\u4e86\u4e00\u500b\u540d\u70baproducts\u7684\u8868\uff0c\u5176\u4e2d\u5305\u542b\u4e09\u500b\u5b57\u6bb5\uff1aid\u3001name\u548cprice\u3002price\u5b57\u6bb5\u7684\u6578\u64da\u985e\u578b\u70baREAL\uff0c\u9019\u610f\u5473\u8457\u6211\u5011\u53ef\u4ee5\u5728\u9019\u500b\u5b57\u6bb5\u4e2d\u5b58\u5132\u6d6e\u9ede\u6578\u3002<\/p>\n<h2 id=\"%e6%8f%92%e5%85%a5%e5%92%8c%e6%9f%a5%e8%a9%a2real%e6%95%b8%e6%93%9a-hQuvlegRdW\">\u63d2\u5165\u548c\u67e5\u8a62REAL\u6578\u64da<\/h2>\n<p>\u63d2\u5165REAL\u6578\u64da\u4e5f\u975e\u5e38\u7c21\u55ae\u3002\u4ee5\u4e0b\u662f\u63d2\u5165\u6578\u64da\u7684\u793a\u4f8b\uff1a<\/p>\n<pre><code>INSERT INTO products (name, price) VALUES ('Product A', 19.99);\nINSERT INTO products (name, price) VALUES ('Product B', 29.99);<\/code><\/pre>\n<p>\u67e5\u8a62REAL\u6578\u64da\u6642\uff0c\u6211\u5011\u53ef\u4ee5\u4f7f\u7528SELECT\u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT * FROM products WHERE price &gt; 20.00;<\/code><\/pre>\n<p>\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709\u50f9\u683c\u5927\u65bc20.00\u7684\u7522\u54c1\u3002<\/p>\n<h2 id=\"real%e6%95%b8%e6%93%9a%e9%a1%9e%e5%9e%8b%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-hQuvlegRdW\">REAL\u6578\u64da\u985e\u578b\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5118\u7ba1REAL\u6578\u64da\u985e\u578b\u5728\u8a31\u591a\u60c5\u6cc1\u4e0b\u90fd\u975e\u5e38\u6709\u7528\uff0c\u4f46\u5728\u4f7f\u7528\u6642\u4ecd\u9700\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li><strong>\u7cbe\u5ea6\u554f\u984c\uff1a<\/strong>\u7531\u65bc\u6d6e\u9ede\u6578\u7684\u8868\u793a\u65b9\u5f0f\uff0c\u67d0\u4e9b\u6578\u5b57\u53ef\u80fd\u7121\u6cd5\u7cbe\u78ba\u8868\u793a\uff0c\u9019\u53ef\u80fd\u5c0e\u81f4\u8a08\u7b97\u7d50\u679c\u51fa\u73fe\u8aa4\u5dee\u3002<\/li>\n<li><strong>\u6bd4\u8f03\u64cd\u4f5c\uff1a<\/strong>\u5728\u9032\u884c\u6d6e\u9ede\u6578\u6bd4\u8f03\u6642\uff0c\u61c9\u8b39\u614e\u8655\u7406\uff0c\u56e0\u70ba\u6d6e\u9ede\u6578\u7684\u7cbe\u5ea6\u554f\u984c\u53ef\u80fd\u5f71\u97ff\u6bd4\u8f03\u7d50\u679c\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-hQuvlegRdW\">\u7e3d\u7d50<\/h2>\n<p>REAL\u6578\u64da\u985e\u578b\u5728MySQL\u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u9069\u5408\u7528\u65bc\u9700\u8981\u6d6e\u9ede\u6578\u7684\u61c9\u7528\u5834\u666f\u3002\u4e86\u89e3\u5176\u7279\u6027\u548c\u4f7f\u7528\u65b9\u6cd5\uff0c\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u6709\u6548\u5730\u8a2d\u8a08\u6578\u64da\u5eab\u7d50\u69cb\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u5b58\u5132\u548c\u8a08\u7b97\u7684\u61c9\u7528\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u81f3\u95dc\u91cd\u8981\u3002\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4f86\u904b\u884c\u60a8\u7684MySQL\u6578\u64da\u5eab\uff0cServer.HK\u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u6eff\u8db3\u4e0d\u540c\u9700\u6c42\u7684\u7528\u6236\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MySQL\u4e2d\u7684REAL\u6307\u4ee4\uff0c\u5b78\u7fd2\u5982\u4f55\u4f7f\u7528\u5be6\u6578\u985e\u578b\u5b58\u5132\u7cbe\u78ba\u6578\u64da\uff0c\u63d0\u5347\u6578\u64da\u5eab\u6027\u80fd\u8207\u6e96\u78ba\u6027\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-79544","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/79544","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=79544"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/79544\/revisions"}],"predecessor-version":[{"id":79545,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/79544\/revisions\/79545"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=79544"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=79544"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=79544"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}