{"id":200960,"date":"2025-05-06T11:13:32","date_gmt":"2025-05-06T03:13:32","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200960\/"},"modified":"2025-05-06T11:13:32","modified_gmt":"2025-05-06T03:13:32","slug":"mysql-%e5%ad%98%e5%82%a8%e8%bf%87%e7%a8%8b%e7%bb%9f%e8%ae%a1%e5%ad%a6%e7%94%9f%e5%88%86%e6%95%b0%e6%97%b6%e4%b8%ba%e4%bd%95%e5%a7%8b%e7%bb%88%e8%be%93%e5%87%ba-num-%e4%b8%ba-0%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200960\/","title":{"rendered":"MySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570\u65f6\u4e3a\u4f55\u59cb\u7ec8\u8f93\u51fa Num \u4e3a 0\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570\u65f6\u4e3a\u4f55\u59cb\u7ec8\u8f93\u51fa Num \u4e3a 0\uff1f<\/h1>\n<p>\u5c0f\u4f19\u4f34\u4eec\u5bf9\u6570\u636e\u5e93\u7f16\u7a0b\u611f\u5174\u8da3\u5417\uff1f\u662f\u5426\u6b63\u5728\u5b66\u4e60\u76f8\u5173\u77e5\u8bc6\u70b9\uff1f\u5982\u679c\u662f\uff0c\u90a3\u4e48\u672c\u6587\u300aMySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570\u65f6\u4e3a\u4f55\u59cb\u7ec8\u8f93\u51fa Num \u4e3a 0\uff1f\u300b\uff0c\u5c31\u5f88\u9002\u5408\u4f60\uff0c\u672c\u7bc7\u6587\u7ae0\u8bb2\u89e3\u7684\u77e5\u8bc6\u70b9\u4e3b\u8981\u5305\u62ec\u3002\u5728\u4e4b\u540e\u7684\u6587\u7ae0\u4e2d\u4e5f\u4f1a\u591a\u591a\u5206\u4eab\u76f8\u5173\u77e5\u8bc6\u70b9\uff0c\u5e0c\u671b\u5bf9\u5927\u5bb6\u7684\u77e5\u8bc6\u79ef\u7d2f\u6709\u6240\u5e2e\u52a9\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241123\/173233408267415202ddd5a.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>\u95ee\u9898\uff1amysql \u5b58\u50a8\u8fc7\u7a0b\u8f93\u51fa\u7684 num \u4e3a\u4f55\u59cb\u7ec8\u4e3a 0\uff1f<\/strong><\/p>\n<p>\u5728\u7f16\u5199\u4e00\u4e2a\u7edf\u8ba1 sc \u8868\u4e2d\u5206\u6570\u4f4e\u4e8e 60 \u5206\u7684\u5b66\u751f\uff08sno\uff09\u6570\u91cf\u7684\u5b58\u50a8\u8fc7\u7a0b\u65f6\uff0c\u95ee\u9898\u63cf\u8ff0\u4e2d\u63d0\u5230\u7684\u4ee3\u7801\u4e00\u76f4\u8f93\u51fa num \u4e3a 0\uff0c\u867d\u7136\u5df2\u7ecf\u8c03\u8bd5\u4e86\u5f88\u957f\u65f6\u95f4\u3002<\/p>\n<p><strong>\u56de\u7b54\uff1a<\/strong><\/p>\n<p>\u89e3\u51b3\u95ee\u9898\u5173\u952e\u5728\u4e8e\u4f7f\u7528\u6e38\u6807\u65f6\u5982\u4f55\u5904\u7406\u7a7a\u503c\u3002\u5b58\u50a8\u8fc7\u7a0b\u4e2d\uff0ctempsno \u53d8\u91cf\u88ab\u58f0\u660e\u4e3a varchar(30)\uff0c\u4f46\u6ca1\u6709\u6307\u5b9a\u9ed8\u8ba4\u503c\u3002\u5f53\u8be5\u53d8\u91cf\u7b2c\u4e00\u6b21\u88ab\u8bfb\u53d6\u65f6\uff0c\u5176\u503c\u662f null\uff0c\u8fd9\u4f1a\u5bfc\u81f4 if(tsno!=tempsno) \u59cb\u7ec8\u4e3a null\u3002<\/p>\n<p>\u56e0\u6b64\uff0c\u4e3a\u4e86\u89e3\u51b3\u8be5\u95ee\u9898\uff0c\u9700\u8981\u5728\u58f0\u660e tempsno \u53d8\u91cf\u65f6\u4e3a\u5176\u6307\u5b9a\u4e00\u4e2a\u9ed8\u8ba4\u503c\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre>declare TempSno varchar(30) default '';<\/pre>\n<p>\u6dfb\u52a0\u9ed8\u8ba4\u503c\u540e\uff0cif(tsno!=tempsno) \u5c31\u53ef\u4ee5\u6b63\u786e\u6bd4\u8f83 tsno \u548c tempsno \u7684\u503c\uff0c\u4ece\u800c\u6b63\u786e\u7edf\u8ba1\u7b26\u5408\u6761\u4ef6\u7684\u5b66\u751f\u6570\u91cf\u3002<\/p>\n<p>\u503c\u5f97\u6ce8\u610f\u7684\u662f\uff0c\u5c3d\u7ba1\u5b58\u50a8\u8fc7\u7a0b\u662f\u89e3\u51b3\u6b64\u7c7b\u95ee\u9898\u7684\u6709\u6548\u5de5\u5177\uff0c\u4f46\u5bf9\u4e8e\u7b80\u5355\u7684\u7edf\u8ba1\u67e5\u8be2\uff0csql \u8bed\u53e5\u5b9e\u9645\u4e0a\u662f\u66f4\u7b80\u6d01\u9ad8\u6548\u7684\u65b9\u6cd5\u3002<\/p>\n<p>\u5230\u8fd9\u91cc\uff0c\u6211\u4eec\u4e5f\u5c31\u8bb2\u5b8c\u4e86\u300aMySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570\u65f6\u4e3a\u4f55\u59cb\u7ec8\u8f93\u51fa Num \u4e3a 0\uff1f\u300b\u7684\u5185\u5bb9\u4e86\u3002\u4e2a\u4eba\u8ba4\u4e3a\uff0c\u57fa\u7840\u77e5\u8bc6\u7684\u5b66\u4e60\u548c\u5de9\u56fa\uff0c\u662f\u4e3a\u4e86\u66f4\u597d\u7684\u5c06\u5176\u8fd0\u7528\u5230\u9879\u76ee\u4e2d\uff0c\u6b22\u8fce\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\uff0c\u5e26\u4f60\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u77e5\u8bc6\u70b9\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570&#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-200960","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200960","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=200960"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200960\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200960"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200960"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200960"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}