{"id":7112,"date":"2024-11-14T09:31:43","date_gmt":"2024-11-14T01:31:43","guid":{"rendered":"https:\/\/fwq.ai\/blog\/7112\/"},"modified":"2024-11-14T09:31:43","modified_gmt":"2024-11-14T01:31:43","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:\/\/fwq.ai\/blog\/7112\/","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":"

\"MySQL<\/p>\n

\u95ee\u9898\uff1a \u5b58\u50a8\u8fc7\u7a0b\u8f93\u51fa\u7684 num \u4e3a\u4f55\u59cb\u7ec8\u4e3a 0\uff1f<\/strong><\/p>\n

\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

\u56de\u7b54\uff1a<\/strong><\/p>\n

\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

\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

declare TempSno varchar(30) default '';<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\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
\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
\u4ee5\u4e0a\u5c31\u662fMySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570\u65f6\u4e3a\u4f55\u59cb\u7ec8\u8f93\u51fa Num \u4e3a 0\uff1f\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
\u95ee\u9898\uff1a \u5b58\u50a8\u8fc7\u7a0b\u8f93\u51fa\u7684 num \u4e3a\u4f55\u59cb\u7ec8\u4e3a 0\uff1f \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 \u56de\u7b54\uff1a \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 \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 declare TempSno varchar(30) default ”; \u767b\u5f55\u540e\u590d\u5236 \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 \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 \u4ee5\u4e0a\u5c31\u662fMySQL \u5b58\u50a8\u8fc7\u7a0b\u7edf\u8ba1\u5b66\u751f\u5206\u6570\u65f6\u4e3a\u4f55\u59cb\u7ec8\u8f93\u51fa Num \u4e3a 0\uff1f\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-7112","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7112","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=7112"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/7112\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=7112"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=7112"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=7112"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}