{"id":200967,"date":"2025-05-06T14:17:11","date_gmt":"2025-05-06T06:17:11","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200967\/"},"modified":"2025-05-06T14:17:11","modified_gmt":"2025-05-06T06:17:11","slug":"mysql-%e4%b8%ad%e7%9a%84%e5%ad%97%e7%ac%a6%e4%b8%b2%e5%a6%82%e4%bd%95%e9%9a%90%e5%bc%8f%e8%bd%ac%e6%8d%a2%e4%b8%ba%e6%95%b0%e5%ad%97%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200967\/","title":{"rendered":"MySQL \u4e2d\u7684\u5b57\u7b26\u4e32\u5982\u4f55\u9690\u5f0f\u8f6c\u6362\u4e3a\u6570\u5b57\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u4e2d\u7684\u5b57\u7b26\u4e32\u5982\u4f55\u9690\u5f0f\u8f6c\u6362\u4e3a\u6570\u5b57\uff1f<\/h1>\n<p>\u4e00\u5206\u8015\u8018\uff0c\u4e00\u5206\u6536\u83b7\uff01\u65e2\u7136\u90fd\u6253\u5f00\u8fd9\u7bc7\uff0c\u5c31\u575a\u6301\u770b\u4e0b\u53bb\uff0c\u5b66\u4e0b\u53bb\u5427\uff01\u672c\u6587\u4e3b\u8981\u4f1a\u7ed9\u5927\u5bb6\u8bb2\u5230\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u5927\u5bb6\u5bf9\u672c\u6587\u6709\u597d\u7684\u5efa\u8bae\u6216\u8005\u770b\u5230\u6709\u4e0d\u8db3\u4e4b\u5904\uff0c\u975e\u5e38\u6b22\u8fce\u5927\u5bb6\u79ef\u6781\u63d0\u51fa\uff01\u5728\u540e\u7eed\u6587\u7ae0\u6211\u4f1a\u7ee7\u7eed\u66f4\u65b0\u76f8\u5173\u7684\u5185\u5bb9\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u90fd\u6709\u6240\u5e2e\u52a9\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241123\/173234867767418b052fa15.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>mysql\u6570\u636e\u7c7b\u578b\u8f6c\u6362\u67e5\u8be2<\/strong><\/p>\n<p>mysql\u4e2d\u7684\u6570\u636e\u7c7b\u578b\u8f6c\u6362\u5728\u67e5\u8be2\u4e2d\u5177\u6709\u9690\u5f0f\u8f6c\u6362\u7684\u80fd\u529b\u3002\u867d\u7136gender\u5217\u5b9a\u4e49\u4e3aint\u578b\uff0c\u4f46when gender = &#8220;m&#8221;\u6761\u4ef6\u4ecd\u7136\u80fd\u591f\u67e5\u8be2\u51fa\u6570\u636e\uff0c\u539f\u56e0\u5728\u4e8emysql\u5bf9\u5b57\u7b26\u4e32\u8fdb\u884c\u4e86\u9690\u5f0f\u8f6c\u6362\u3002<\/p>\n<p>\u5728mysql\u4e2d\uff0c\u5b57\u7b26\u4e32\u7c7b\u578b\u53ef\u4ee5\u81ea\u52a8\u8f6c\u6362\u4e3a\u6570\u5b57\u7c7b\u578b\u3002\u5f53\u5b57\u7b26\u4e32\u4e3a\u6574\u6570\u8868\u793a\u65f6\uff0c\u5b57\u7b26\u4e32\u5c06\u88ab\u9690\u5f0f\u8f6c\u6362\u4e3a\u76f8\u5e94\u7684\u6570\u5b57\u3002\u56e0\u6b64\uff0c\u5f53\u60a8\u4f7f\u7528where gender = &#8220;m&#8221;\u65f6\uff0cmysql\u5c06\u5b57\u7b26\u4e32&#8221;m&#8221;\u8f6c\u6362\u4e3a\u6570\u5b571\uff0c\u7136\u540e\u4e0egender\u5217\u503c\u8fdb\u884c\u6bd4\u8f83\u3002\u7531\u4e8egender\u5217\u7684\u503c\u662f\u5c0f\u5199\u5b57\u6bcd\u201cm\u201d\uff0c\u5b83\u5728ascii\u7801\u4e2d\u5bf9\u5e94\u4e8e\u6570\u5b571\uff0c\u56e0\u6b64\u67e5\u8be2\u6210\u529f\u8fd4\u56de\u7ed3\u679c\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u4ee5\u4e0b\u67e5\u8be2\u5c06\u8f93\u51fa0\uff1a<\/p>\n<pre>select cast('M' AS DECIMAL);<\/pre>\n<p>\u8fd9\u8868\u660emysql\u5c06\u5b57\u7b26\u4e32&#8221;m&#8221;\u9690\u5f0f\u8f6c\u6362\u4e3a\u6570\u5b571\uff0c\u7136\u540e\u5c06\u5176\u8f6c\u6362\u4e3adecimal\u6570\u636e\u7c7b\u578b\uff0c\u5f97\u52300\u3002<\/p>\n<p>\u9700\u8981\u4e86\u89e3\u7684\u662f\uff0c\u4e0d\u540c\u7248\u672c\u6216\u4e0d\u540c\u914d\u7f6e\u7684mysql\uff0c\u5bf9\u6570\u636e\u7c7b\u578b\u8f6c\u6362\u7684\u5904\u7406\u53ef\u80fd\u6709\u5dee\u5f02\u3002\u56e0\u6b64\uff0c\u5efa\u8bae\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u660e\u786e\u6307\u5b9a\u6570\u636e\u7c7b\u578b\u4ee5\u907f\u514d\u610f\u5916\u8f6c\u6362\u3002<\/p>\n<p>\u7ec8\u4e8e\u4ecb\u7ecd\u5b8c\u5566\uff01\u5c0f\u4f19\u4f34\u4eec\uff0c\u8fd9\u7bc7\u5173\u4e8e\u300aMySQL \u4e2d\u7684\u5b57\u7b26\u4e32\u5982\u4f55\u9690\u5f0f\u8f6c\u6362\u4e3a\u6570\u5b57\uff1f\u300b\u7684\u4ecb\u7ecd\u5e94\u8be5\u8ba9\u4f60\u6536\u83b7\u591a\u591a\u4e86\u5427\uff01\u6b22\u8fce\u5927\u5bb6\u6536\u85cf\u6216\u5206\u4eab\u7ed9\u66f4\u591a\u9700\u8981\u5b66\u4e60\u7684\u670b\u53cb\u5427~\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u4e5f\u4f1a\u53d1\u5e03\u6570\u636e\u5e93\u76f8\u5173\u77e5\u8bc6\uff0c\u5feb\u6765\u5173\u6ce8\u5427\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u4e2d\u7684\u5b57\u7b26\u4e32\u5982\u4f55\u9690\u5f0f\u8f6c&#46;&#46;&#46;<\/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-200967","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200967","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=200967"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200967\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200967"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200967"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}