{"id":78634,"date":"2024-10-16T12:09:15","date_gmt":"2024-10-16T04:09:15","guid":{"rendered":"https:\/\/server.hk\/cnblog\/78634\/"},"modified":"2024-10-16T12:09:15","modified_gmt":"2024-10-16T04:09:15","slug":"mysql%e6%8c%87%e4%bb%a4-if%ef%bc%88%e6%a2%9d%e4%bb%b6%e8%aa%9e%e5%8f%a5%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/78634\/","title":{"rendered":"MySQL\u6307\u4ee4: IF\uff08\u689d\u4ef6\u8a9e\u53e5\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-if%ef%bc%88%e6%a2%9d%e4%bb%b6%e8%aa%9e%e5%8f%a5%ef%bc%89-gPeVNprTwJ\">MySQL\u6307\u4ee4: IF\uff08\u689d\u4ef6\u8a9e\u53e5\uff09<\/h1>\n<p>\u5728\u6578\u64da\u5eab\u7ba1\u7406\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u95dc\u806f\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\u4f86\u8655\u7406\u548c\u67e5\u8a62\u6578\u64da\uff0c\u5176\u4e2d\u4e4b\u4e00\u5c31\u662f\u689d\u4ef6\u8a9e\u53e5\u7684\u4f7f\u7528\u3002IF\u8a9e\u53e5\u662fMySQL\u4e2d\u4e00\u500b\u975e\u5e38\u91cd\u8981\u7684\u689d\u4ef6\u8a9e\u53e5\uff0c\u80fd\u5920\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u57f7\u884c\u4e0d\u540c\u7684\u64cd\u4f5c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eMySQL\u4e2d\u7684IF\u8a9e\u53e5\uff0c\u5305\u62ec\u5176\u8a9e\u6cd5\u3001\u7528\u6cd5\u53ca\u5be6\u969b\u7bc4\u4f8b\u3002<\/p>\n<h2 id=\"if%e8%aa%9e%e5%8f%a5%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-gPeVNprTwJ\">IF\u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>IF\u8a9e\u53e5\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>IF(condition, true_value, false_value)<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0c<code>condition<\/code>\u662f\u9700\u8981\u8a55\u4f30\u7684\u689d\u4ef6\uff0c<code>true_value<\/code>\u662f\u5728\u689d\u4ef6\u70ba\u771f\u6642\u8fd4\u56de\u7684\u503c\uff0c\u800c<code>false_value<\/code>\u5247\u662f\u5728\u689d\u4ef6\u70ba\u5047\u6642\u8fd4\u56de\u7684\u503c\u3002<\/p>\n<h2 id=\"if%e8%aa%9e%e5%8f%a5%e7%9a%84%e4%bd%bf%e7%94%a8%e5%a0%b4%e6%99%af-gPeVNprTwJ\">IF\u8a9e\u53e5\u7684\u4f7f\u7528\u5834\u666f<\/h2>\n<p>IF\u8a9e\u53e5\u901a\u5e38\u7528\u65bc\u4ee5\u4e0b\u5e7e\u7a2e\u60c5\u6cc1\uff1a<\/p>\n<ul>\n<li>\u6839\u64da\u67d0\u4e9b\u689d\u4ef6\u4f86\u6c7a\u5b9a\u986f\u793a\u7684\u6578\u64da\u3002<\/li>\n<li>\u5728\u67e5\u8a62\u4e2d\u9032\u884c\u6578\u64da\u7684\u8f49\u63db\u6216\u8a08\u7b97\u3002<\/li>\n<li>\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u9032\u884c\u908f\u8f2f\u5224\u65b7\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%af%84%e4%be%8b%ef%bc%9a%e4%bd%bf%e7%94%a8if%e8%aa%9e%e5%8f%a5%e9%80%b2%e8%a1%8c%e6%95%b8%e6%93%9a%e6%9f%a5%e8%a9%a2-gPeVNprTwJ\">\u7bc4\u4f8b\uff1a\u4f7f\u7528IF\u8a9e\u53e5\u9032\u884c\u6578\u64da\u67e5\u8a62<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba<code>employees<\/code>\u7684\u8868\u683c\uff0c\u8a72\u8868\u683c\u5305\u542b\u54e1\u5de5\u7684\u59d3\u540d\u548c\u85aa\u6c34\u3002\u6211\u5011\u5e0c\u671b\u6839\u64da\u85aa\u6c34\u7684\u9ad8\u4f4e\u4f86\u6a19\u8a18\u54e1\u5de5\u7684\u7b49\u7d1a\u3002\u4ee5\u4e0b\u662f\u4f7f\u7528IF\u8a9e\u53e5\u7684\u67e5\u8a62\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>SELECT name, salary,\n    IF(salary &gt; 50000, '\u9ad8\u7d1a', '\u666e\u901a') AS level\nFROM employees;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u67e5\u8a62\u4e2d\uff0c\u7576\u85aa\u6c34\u5927\u65bc50000\u6642\uff0c<code>level<\/code>\u5c07\u986f\u793a\u70ba\u300c\u9ad8\u7d1a\u300d\uff0c\u5426\u5247\u986f\u793a\u70ba\u300c\u666e\u901a\u300d\u3002\u9019\u6a23\u7684\u67e5\u8a62\u80fd\u5920\u5e6b\u52a9\u6211\u5011\u5feb\u901f\u4e86\u89e3\u54e1\u5de5\u7684\u85aa\u6c34\u7b49\u7d1a\u3002<\/p>\n<h2 id=\"%e5%9c%a8%e5%ad%98%e5%84%b2%e9%81%8e%e7%a8%8b%e4%b8%ad%e4%bd%bf%e7%94%a8if%e8%aa%9e%e5%8f%a5-gPeVNprTwJ\">\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528IF\u8a9e\u53e5<\/h2>\n<p>IF\u8a9e\u53e5\u4e5f\u53ef\u4ee5\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\u4f7f\u7528\uff0c\u4ee5\u5be6\u73fe\u66f4\u8907\u96dc\u7684\u908f\u8f2f\u3002\u4f8b\u5982\uff0c\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684\u5b58\u5132\u904e\u7a0b\uff0c\u6839\u64da\u54e1\u5de5\u7684\u85aa\u6c34\u4f86\u6c7a\u5b9a\u662f\u5426\u7d66\u4e88\u734e\u91d1\uff1a<\/p>\n<pre><code>DELIMITER \/\/\nCREATE PROCEDURE give_bonus(IN emp_id INT)\nBEGIN\n    DECLARE emp_salary DECIMAL(10,2);\n    \n    SELECT salary INTO emp_salary FROM employees WHERE id = emp_id;\n    \n    IF emp_salary &gt; 60000 THEN\n        UPDATE employees SET bonus = 1000 WHERE id = emp_id;\n    ELSE\n        UPDATE employees SET bonus = 500 WHERE id = emp_id;\n    END IF;\nEND \/\/\nDELIMITER ;<\/code><\/pre>\n<p>\u5728\u9019\u500b\u5b58\u5132\u904e\u7a0b\u4e2d\uff0c\u6211\u5011\u9996\u5148\u6839\u64da\u54e1\u5de5ID\u67e5\u8a62\u85aa\u6c34\uff0c\u7136\u5f8c\u6839\u64da\u85aa\u6c34\u7684\u9ad8\u4f4e\u6c7a\u5b9a\u734e\u91d1\u7684\u6578\u984d\u3002\u9019\u6a23\u7684\u908f\u8f2f\u5224\u65b7\u4f7f\u5f97\u6578\u64da\u8655\u7406\u66f4\u52a0\u9748\u6d3b\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-gPeVNprTwJ\">\u7e3d\u7d50<\/h2>\n<p>MySQL\u4e2d\u7684IF\u8a9e\u53e5\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u6839\u64da\u4e0d\u540c\u7684\u689d\u4ef6\u57f7\u884c\u4e0d\u540c\u7684\u64cd\u4f5c\u3002\u7121\u8ad6\u662f\u5728\u67e5\u8a62\u4e2d\u9084\u662f\u5728\u5b58\u5132\u904e\u7a0b\u4e2d\uff0cIF\u8a9e\u53e5\u90fd\u80fd\u5920\u5e6b\u52a9\u958b\u767c\u8005\u5be6\u73fe\u66f4\u8907\u96dc\u7684\u908f\u8f2f\u5224\u65b7\u3002\u900f\u904e\u672c\u6587\u7684\u4ecb\u7d39\uff0c\u5e0c\u671b\u80fd\u5920\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u61c9\u7528MySQL\u7684IF\u8a9e\u53e5\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u7684\u6548\u7387\u3002<\/p>\n<p>\u5982\u679c\u60a8\u5c0d\u65bc<code>VPS<\/code>\u3001<code>\u9999\u6e2fVPS<\/code>\u6216\u5176\u4ed6\u76f8\u95dc\u7684<code>\u4e91\u670d\u52a1\u5668<\/code>\u6709\u8208\u8da3\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9 <a href=\"https:\/\/server.hk\">Server.HK<\/a> \u7372\u53d6\u66f4\u591a\u8cc7\u8a0a\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MySQL\u4e2d\u7684IF\u689d\u4ef6\u8a9e\u53e5\uff0c\u5b78\u7fd2\u5982\u4f55\u6839\u64da\u7279\u5b9a\u689d\u4ef6\u57f7\u884c\u4e0d\u540c\u7684\u64cd\u4f5c\uff0c\u63d0\u5347\u6578\u64da\u5eab\u67e5\u8a62\u6548\u7387\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-78634","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78634","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=78634"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78634\/revisions"}],"predecessor-version":[{"id":78641,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78634\/revisions\/78641"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=78634"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=78634"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=78634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}