{"id":231,"date":"2024-06-18T12:34:24","date_gmt":"2024-06-18T04:34:24","guid":{"rendered":"http:\/\/zhaoyanqi.cn\/?p=231"},"modified":"2024-06-18T12:34:25","modified_gmt":"2024-06-18T04:34:25","slug":"mysql%e6%b5%81%e7%a8%8b%e6%8e%a7%e5%88%b6","status":"publish","type":"post","link":"https:\/\/zhaoyanqi.cn\/?p=231","title":{"rendered":"mysql\u6d41\u7a0b\u63a7\u5236"},"content":{"rendered":"\n<h3 class=\"wp-block-heading\" id=\"14868ad9\">\u4e00\u3001\u6761\u4ef6\u8bed\u53e5<\/h3>\n\n\n\n<p id=\"ud0b0706b\">\u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\u7684 SQL \u6761\u4ef6\u8bed\u53e5\uff0c\u5b83\u4f7f\u7528\u4e86 <code>IF<\/code>\u3001<code>ELSEIF<\/code> \u548c <code>ELSE<\/code> \u7ed3\u6784\uff1a<\/p>\n\n\n\n<pre id=\"1eb74177\" class=\"wp-block-code\"><code>delimiter \/\/\nCREATE PROCEDURE proc_if ()\nBEGIN\n    DECLARE i INT DEFAULT 0;\n    IF i = 1 THEN\n        SELECT 1;\n    ELSEIF i = 2 THEN\n        SELECT 2;\n    ELSE\n        SELECT 7;\n    END IF;\nEND \/\/\ndelimiter ;<\/code><\/pre>\n\n\n\n<p id=\"u964fbb25\">\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u6839\u636e\u53d8\u91cf <code>i<\/code> \u7684\u503c\u6765\u9009\u62e9\u4e0d\u540c\u7684\u7ed3\u679c\u3002\u5982\u679c <code>i<\/code> \u7b49\u4e8e 1\uff0c\u5219\u9009\u62e9 1\uff1b\u5982\u679c <code>i<\/code> \u7b49\u4e8e 2\uff0c\u5219\u9009\u62e9 2\uff1b\u5426\u5219\uff0c\u9009\u62e9 7\u3002<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"5e971845\">\u4e8c\u3001\u5faa\u73af\u8bed\u53e5<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"9b3ad943\">1. <code>WHILE<\/code> \u5faa\u73af<\/h4>\n\n\n\n<p id=\"u1c1fa9c7\">\u4ee5\u4e0b\u662f\u4e00\u4e2a\u4f7f\u7528 <code>WHILE<\/code> \u5faa\u73af\u7684\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre id=\"a545a366\" class=\"wp-block-code\"><code>delimiter \/\/\nCREATE PROCEDURE proc_while ()\nBEGIN\n    DECLARE num INT;\n    SET num = 0;\n    WHILE num &lt; 10 DO\n        SELECT num;\n        SET num = num + 1;\n    END WHILE;\nEND \/\/\ndelimiter ;<\/code><\/pre>\n\n\n\n<p id=\"ube87bc06\">\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c<code>WHILE<\/code> \u5faa\u73af\u7528\u4e8e\u91cd\u590d\u6267\u884c\u4e00\u7ec4 SQL \u8bed\u53e5\uff0c\u76f4\u5230 <code>num<\/code> \u4e0d\u5c0f\u4e8e 10 \u4e3a\u6b62\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"f28cd27b\">2. <code>REPEAT<\/code> \u5faa\u73af<\/h4>\n\n\n\n<p id=\"ua4a9b497\">\u4ee5\u4e0b\u662f\u4e00\u4e2a\u4f7f\u7528 <code>REPEAT<\/code> \u5faa\u73af\u7684\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre id=\"88966c10\" class=\"wp-block-code\"><code>delimiter \/\/\nCREATE PROCEDURE proc_repeat ()\nBEGIN\n    DECLARE i INT;\n    SET i = 0;\n    REPEAT\n        SELECT i;\n        SET i = i + 1;\n    UNTIL i &gt;= 5\n    END REPEAT;\nEND \/\/\ndelimiter ;<\/code><\/pre>\n\n\n\n<p id=\"u537f1fd4\">\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c<code>REPEAT<\/code> \u5faa\u73af\u4f1a\u91cd\u590d\u6267\u884c SQL \u8bed\u53e5\uff0c\u76f4\u5230 <code>UNTIL<\/code> \u6761\u4ef6\u4e3a\u771f\u65f6\u505c\u6b62\u5faa\u73af\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"d64a188d\">3. <code>LOOP<\/code> \u5faa\u73af<\/h4>\n\n\n\n<p id=\"u572e7c58\">\u4ee5\u4e0b\u662f\u4e00\u4e2a\u4f7f\u7528 <code>LOOP<\/code> \u5faa\u73af\u7684\u793a\u4f8b\uff1a<\/p>\n\n\n\n<pre id=\"0fb050b7\" class=\"wp-block-code\"><code>delimiter \/\/\nCREATE PROCEDURE proc_loop ()\nBEGIN\n    DECLARE i INT DEFAULT 0;\n    loop_label: LOOP\n        SET i = i + 1;\n        IF i &lt; 8 THEN\n            ITERATE loop_label;\n        END IF;\n        IF i &gt;= 10 THEN\n            LEAVE loop_label;\n        END IF;\n        SELECT i;\n    END LOOP loop_label;\nEND \/\/\ndelimiter ;<\/code><\/pre>\n\n\n\n<p id=\"uf484ff21\">\u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c<code>LOOP<\/code> \u5faa\u73af\u7528\u4e8e\u91cd\u590d\u6267\u884c\u4e00\u7ec4 SQL \u8bed\u53e5\u3002\u4f7f\u7528 <code>ITERATE<\/code> \u8bed\u53e5\u53ef\u4ee5\u8df3\u8fc7\u5faa\u73af\u7684\u5f53\u524d\u8fed\u4ee3\u5e76\u7ee7\u7eed\u4e0b\u4e00\u4e2a\u8fed\u4ee3\uff0c\u800c\u4f7f\u7528 <code>LEAVE<\/code> \u8bed\u53e5\u5219\u53ef\u4ee5\u7ec8\u6b62\u5faa\u73af\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00\u3001\u6761\u4ef6\u8bed\u53e5 \u4ee5\u4e0b\u662f\u4e00\u4e2a\u793a\u4f8b\u7684 SQL \u6761\u4ef6\u8bed\u53e5\uff0c\u5b83\u4f7f\u7528\u4e86 IF\u3001ELSEIF \u548c ELSE \u7ed3\u6784\uff1a \u5728\u8fd9\u4e2a\u8fc7 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,12],"tags":[],"class_list":["post-231","post","type-post","status-publish","format-standard","hentry","category-mysql","category-sql"],"_links":{"self":[{"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=\/wp\/v2\/posts\/231","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=231"}],"version-history":[{"count":1,"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=\/wp\/v2\/posts\/231\/revisions"}],"predecessor-version":[{"id":232,"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=\/wp\/v2\/posts\/231\/revisions\/232"}],"wp:attachment":[{"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zhaoyanqi.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}