{"id":201069,"date":"2025-05-06T11:57:06","date_gmt":"2025-05-06T03:57:06","guid":{"rendered":"https:\/\/server.hk\/cnblog\/201069\/"},"modified":"2025-05-06T11:57:06","modified_gmt":"2025-05-06T03:57:06","slug":"mysql-%e4%b8%ad%e4%bd%bf%e7%94%a8%e7%ad%89%e5%8f%b7%e6%9f%a5%e8%af%a2%e4%b8%ba%e4%bd%95%e5%87%ba%e7%8e%b0%e6%a8%a1%e7%b3%8a%e5%8c%b9%e9%85%8d%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/201069\/","title":{"rendered":"MySQL \u4e2d\u4f7f\u7528\u7b49\u53f7\u67e5\u8be2\u4e3a\u4f55\u51fa\u73b0\u6a21\u7cca\u5339\u914d\uff1f"},"content":{"rendered":"<p><b><\/b> <\/p>\n<h1>MySQL \u4e2d\u4f7f\u7528\u7b49\u53f7\u67e5\u8be2\u4e3a\u4f55\u51fa\u73b0\u6a21\u7cca\u5339\u914d\uff1f<\/h1>\n<p>\u5927\u5bb6\u597d\uff0c\u6211\u4eec\u53c8\u89c1\u9762\u4e86\u554a~\u672c\u6587\u7684\u5185\u5bb9\u4e2d\u5c06\u4f1a\u6d89\u53ca\u5230\u7b49\u7b49\u3002\u5982\u679c\u4f60\u6b63\u5728\u5b66\u4e60\u76f8\u5173\u77e5\u8bc6\uff0c\u6b22\u8fce\u5173\u6ce8\u6211\uff0c\u4ee5\u540e\u4f1a\u7ed9\u5927\u5bb6\u5e26\u6765\u66f4\u591a\u76f8\u5173\u6587\u7ae0\uff0c\u5e0c\u671b\u6211\u4eec\u80fd\u4e00\u8d77\u8fdb\u6b65\uff01\u4e0b\u9762\u5c31\u5f00\u59cb\u672c\u6587\u7684\u6b63\u5f0f\u5185\u5bb9~<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.17golang.com\/uploads\/20241129\/173285680467494be459b2c.jpg\" class=\"aligncenter\"><\/p>\n<p><strong>MySQL \u4e2d\u4f7f\u7528\u7b49\u53f7\u8fdb\u884c\u5224\u65ad\uff0c\u4e3a\u4f55\u67e5\u8be2\u7ed3\u679c\u5448\u73b0\u6a21\u7cca\u5339\u914d\uff1f<\/strong><\/p>\n<p>\u5728 MySQL \u4e2d\uff0c\u4f7f\u7528\u7b49\u53f7 (=) \u8fdb\u884c\u5224\u65ad\u65f6\uff0c\u7ed3\u679c\u901a\u5e38\u5e94\u7b26\u5408\u7cbe\u786e\u5339\u914d\u539f\u5219\u3002\u7136\u800c\uff0c\u6709\u65f6\u60a8\u53ef\u80fd\u4f1a\u9047\u5230\u67e5\u8be2\u7ed3\u679c\u8fd1\u4f3c\u4e8e\u6a21\u7cca\u5339\u914d\u7684\u60c5\u51b5\u3002<\/p>\n<p><strong>\u539f\u56e0\u5206\u6790<\/strong><\/p>\n<p>\u8fd9\u53ef\u80fd\u662f\u7531\u4e8e\u4ee5\u4e0b\u539f\u56e0\u4e4b\u4e00\uff1a<\/p>\n<ul>\n<li><strong>\u5b57\u6bb5\u7c7b\u578b\u4e0d\u5339\u914d\uff1a<\/strong>\u786e\u4fdd\u67e5\u8be2\u4e2d\u6d89\u53ca\u5b57\u6bb5\u7684\u7c7b\u578b\u4e0e\u88ab\u6bd4\u8f83\u503c\u5339\u914d\u3002\u5982\u679c\u7c7b\u578b\u4e0d\u4e00\u81f4\uff0cMySQL \u53ef\u80fd\u65e0\u6cd5\u8fdb\u884c\u7cbe\u786e\u6bd4\u8f83\u5e76\u5bfc\u81f4\u6a21\u7cca\u5339\u914d\u3002<\/li>\n<li><strong>\u68c0\u67e5\u7d22\u5f15\uff1a<\/strong>\u7d22\u5f15\u53ef\u4ee5\u52a0\u901f\u67e5\u8be2\uff0c\u4f46\u5982\u679c\u7d22\u5f15\u4e0e\u67e5\u8be2\u6761\u4ef6\u4e0d\u5339\u914d\uff0c\u4e5f\u53ef\u80fd\u5bfc\u81f4\u4e0d\u51c6\u786e\u7684\u7ed3\u679c\u3002\u786e\u4fdd\u4e3a\u67e5\u8be2\u6761\u4ef6\u521b\u5efa\u4e86\u6b63\u786e\u7684\u7d22\u5f15\u3002<\/li>\n<li><strong>\u6392\u5e8f\u5dee\u5f02\uff1a<\/strong>\u5982\u679c\u67e5\u8be2\u6d89\u53ca\u6309\u5b57\u7b26\u4e32\u5217\u6392\u5e8f\uff0c\u8bf7\u786e\u4fdd\u6392\u5e8f\u89c4\u5219\u4e0e\u5b57\u7b26\u4e32\u6bd4\u8f83\u4e2d\u4f7f\u7528\u7684\u5339\u914d\u3002\u4f8b\u5982\uff0c\u4e0d\u533a\u5206\u5927\u5c0f\u5199\u7684\u6bd4\u8f83\u53ef\u80fd\u4ea7\u751f\u6bd4\u533a\u5206\u5927\u5c0f\u5199\u66f4\u5e7f\u6cdb\u7684\u7ed3\u679c\u3002<\/li>\n<li><strong>NULL \u503c\uff1a<\/strong>\u5f53\u6bd4\u8f83 NULL \u503c\u65f6\uff0c\u7ed3\u679c\u53ef\u80fd\u4e0d\u76f4\u89c2\u3002\u6bd4\u8f83 NULL \u503c\u65f6\uff0c\u901a\u5e38\u4f7f\u7528 IS NULL \u6216 IS NOT NULL \u8fd0\u7b97\u7b26\u3002<\/li>\n<\/ul>\n<p><strong>\u89e3\u51b3\u65b9\u6848<\/strong><\/p>\n<p>\u6839\u636e\u60a8\u9047\u5230\u7684\u7279\u5b9a\u60c5\u51b5\uff0c\u53ef\u4ee5\u91c7\u53d6\u4ee5\u4e0b\u6b65\u9aa4\u6765\u89e3\u51b3\u95ee\u9898\uff1a<\/p>\n<ul>\n<li>\u786e\u4fdd\u6d89\u53ca\u5b57\u6bb5\u7684\u7c7b\u578b\u5339\u914d\u3002<\/li>\n<li>\u68c0\u67e5\u7d22\u5f15\u5e76\u6839\u636e\u9700\u8981\u91cd\u65b0\u521b\u5efa\u5b83\u4eec\u3002<\/li>\n<li>\u8c03\u6574\u6392\u5e8f\u89c4\u5219\u4ee5\u5339\u914d\u6bd4\u8f83\u64cd\u4f5c\u3002<\/li>\n<li>\u4f7f\u7528 IS NULL \u6216 IS NOT NULL \u8fd0\u7b97\u7b26\u6b63\u786e\u5904\u7406 NULL \u503c\u3002<\/li>\n<\/ul>\n<p>\u7406\u8bba\u8981\u638c\u63e1\uff0c\u5b9e\u64cd\u4e0d\u80fd\u843d\uff01\u4ee5\u4e0a\u5173\u4e8e\u300aMySQL \u4e2d\u4f7f\u7528\u7b49\u53f7\u67e5\u8be2\u4e3a\u4f55\u51fa\u73b0\u6a21\u7cca\u5339\u914d\uff1f\u300b\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u5927\u5bb6\u90fd\u638c\u63e1\u4e86\u5427\uff01\u5982\u679c\u60f3\u8981\u7ee7\u7eed\u63d0\u5347\u81ea\u5df1\u7684\u80fd\u529b\uff0c\u90a3\u4e48\u5c31\u6765\u5173\u6ce8\u4e3b\u673a\u5b9d\u8d1d\u516c\u4f17\u53f7\u5427\uff01<\/p>\n<dl>\n<dt>\n <\/dt>\n<\/dl>\n","protected":false},"excerpt":{"rendered":"<p>MySQL \u4e2d\u4f7f\u7528\u7b49\u53f7\u67e5\u8be2\u4e3a\u4f55\u51fa&#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-201069","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201069","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=201069"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/201069\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=201069"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=201069"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=201069"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}