{"id":200470,"date":"2025-05-06T08:48:42","date_gmt":"2025-05-06T00:48:42","guid":{"rendered":"https:\/\/server.hk\/cnblog\/200470\/"},"modified":"2025-05-06T08:48:42","modified_gmt":"2025-05-06T00:48:42","slug":"mysql-%e5%ad%98%e5%82%a8%e8%bf%87%e7%a8%8b%e4%b8%ad-num-%e6%80%bb%e6%98%af%e8%be%93%e5%87%ba-0%ef%bc%9a%e4%b8%ba%e4%bb%80%e4%b9%88-tempsno-%e5%8f%98%e9%87%8f%e6%b2%a1%e6%9c%89%e9%bb%98%e8%ae%a4","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/200470\/","title":{"rendered":"MySQL \u5b58\u50a8\u8fc7\u7a0b\u4e2d Num \u603b\u662f\u8f93\u51fa 0\uff1a\u4e3a\u4ec0\u4e48 TempSno \u53d8\u91cf\u6ca1\u6709\u9ed8\u8ba4\u503c\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u5b58\u50a8\u8fc7\u7a0b\u4e2d Num \u603b\u662f\u8f93\u51fa 0\uff1a\u4e3a\u4ec0\u4e48 TempSno \u53d8\u91cf\u6ca1\u6709\u9ed8\u8ba4\u503c\uff1f<\/h1>\n<p>\u201c\u7eb5\u6709\u75be\u98ce\u6765\uff0c\u4eba\u751f\u4e0d\u8a00\u5f03\u201d\uff0c\u8fd9\u53e5\u8bdd\u9001\u7ed9\u6b63\u5728\u5b66\u4e60\u7684\u670b\u53cb\u4eec\uff0c\u4e5f\u5e0c\u671b\u5728\u9605\u8bfb\u672c\u6587\u540e\uff0c\u80fd\u591f\u771f\u7684\u5e2e\u52a9\u5230\u5927\u5bb6\u3002\u6211\u4e5f\u4f1a\u5728\u540e\u7eed\u7684\u6587\u7ae0\u4e2d\uff0c\u9646\u7eed\u66f4\u65b0\u76f8\u5173\u7684\u6280\u672f\u6587\u7ae0\uff0c\u6709\u597d\u7684\u5efa\u8bae\u6b22\u8fce\u5927\u5bb6\u5728\u8bc4\u8bba\u7559\u8a00\uff0c\u975e\u5e38\u611f\u8c22\uff01<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241105\/1730816685672a2aadb5de2.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>\u4e3a\u4ec0\u4e48 mysql \u5b58\u50a8\u8fc7\u7a0b\u4e2d\u7684 num \u603b\u662f\u8f93\u51fa 0<\/strong><\/p>\n<p>\u4f7f\u7528\u5b58\u50a8\u8fc7\u7a0b\u6765\u7edf\u8ba1\u7279\u5b9a\u6761\u4ef6\u7684\u5b66\u751f\u4eba\u6570\u65f6\uff0c\u9047\u5230\u7684\u95ee\u9898\u662f\u8f93\u51fa\u7684 num \u6c38\u8fdc\u4e3a 0\u3002\u8fd9\u662f\u56e0\u4e3a\u5728\u58f0\u660e\u5b58\u50a8\u8fc7\u7a0b\u53d8\u91cf\u65f6\u7f3a\u5c11\u9ed8\u8ba4\u503c\u3002<\/p>\n<p>\u5177\u4f53\u6765\u8bf4\uff0c\u5f53\u58f0\u660e\u53d8\u91cf tempsno \u65f6\u6ca1\u6709\u6307\u5b9a\u9ed8\u8ba4\u503c\u3002\u5f53\u4ece sc \u8868\u4e2d\u83b7\u53d6 student \u7f16\u53f7 (sno) \u548c\u5206\u6570 (score) \u65f6\uff0ctempsno \u7684\u503c\u4fdd\u6301\u4e3a null\u3002\u56e0\u6b64\uff0c\u5f53\u6bd4\u8f83 tsno \u548c tempsno \u65f6\uff0c\u59cb\u7ec8\u8fd4\u56de null\uff0c\u65e0\u6cd5\u8fdb\u5165\u7edf\u8ba1\u6761\u4ef6\u7684 if \u8bed\u53e5\u5757\u3002<\/p>\n<p>\u8981\u89e3\u51b3\u6b64\u95ee\u9898\uff0c\u9700\u8981\u5728\u58f0\u660e tempsno \u53d8\u91cf\u65f6\u6dfb\u52a0\u9ed8\u8ba4\u503c\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre>declare tempsno varchar(30) default '';<\/pre>\n<p>\u901a\u8fc7\u8bbe\u7f6e\u9ed8\u8ba4\u503c\uff0c\u5b58\u50a8\u8fc7\u7a0b\u53ef\u4ee5\u6b63\u786e\u8ddf\u8e2a\u4ece sc \u8868\u4e2d\u83b7\u53d6\u7684 sno\uff0c\u5e76\u5728\u6ee1\u8db3\u6761\u4ef6\u65f6\u6b63\u786e\u589e\u52a0 num\u3002\u4fee\u6539\u540e\u7684\u5b58\u50a8\u8fc7\u7a0b\u5982\u4e0b\uff1a<\/p>\n<pre>begin\n    declare tSno varchar(30);\n    declare tScore numeric(10,2);\n    declare TempSno varchar(30) default '';\n    declare done int default 0;    \n    declare Num int default 0;\n    declare getStudent cursor for select Sno, Score from SC order by Sno;\n    declare continue handler for SQLSTATE '02000' set done = 1;\n    open getStudent;    \n    repeat\n        fetch getStudent into tSno,tScore;\n        if(tScore&amp;lt;60) then\n            if(tSno!=TempSno) then\n            set Num = Num + 1;\n            set TempSno = tSno;\n            end if;\n        end if;\n    until done end repeat;\n    select Num;\n    close getStudent;\n    drop table OrderTable;\nend \/\/\ndelimiter ;\n\ncall countNum();<\/pre>\n<p>\u4fee\u6539\u540e\uff0cnum \u5c06\u6b63\u786e\u8f93\u51fa\u6ee1\u8db3\u6761\u4ef6\u7684\u5b66\u751f\u4eba\u6570\u3002<\/p>\n<p>\u6587\u4e2d\u5173\u4e8e\u7684\u77e5\u8bc6\u4ecb\u7ecd\uff0c\u5e0c\u671b\u5bf9\u4f60\u7684\u5b66\u4e60\u6709\u6240\u5e2e\u52a9\uff01\u82e5\u662f\u53d7\u76ca\u532a\u6d45\uff0c\u90a3\u5c31\u52a8\u52a8\u9f20\u6807\u6536\u85cf\u8fd9\u7bc7\u300aMySQL \u5b58\u50a8\u8fc7\u7a0b\u4e2d Num \u603b\u662f\u8f93\u51fa 0\uff1a\u4e3a\u4ec0\u4e48 TempSno \u53d8\u91cf\u6ca1\u6709\u9ed8\u8ba4\u503c\uff1f\u300b\u6587\u7ae0\u5427\uff0c\u4e5f\u53ef\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u4e86\u89e3\u76f8\u5173\u6280\u672f\u6587\u7ae0\u3002<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u5b58\u50a8\u8fc7\u7a0b\u4e2d Num &#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-200470","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200470","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=200470"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/200470\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=200470"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=200470"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=200470"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}