{"id":59579,"date":"2024-10-12T23:09:23","date_gmt":"2024-10-12T15:09:23","guid":{"rendered":"https:\/\/server.hk\/cnblog\/59579\/"},"modified":"2024-10-12T23:09:23","modified_gmt":"2024-10-12T15:09:23","slug":"char%e9%a1%9e%e5%9e%8b%e6%95%b8%e6%93%9a%e5%ba%ab%e5%ad%97%e6%ae%b5%e7%9a%84%e6%9c%89%e6%95%88%e5%88%a4%e6%96%b7%e6%96%b9%e6%b3%95%e8%a7%a3%e6%9e%90-%e5%a6%82%e4%bd%95%e5%88%a4%e6%96%b7char%e6%9c%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/59579\/","title":{"rendered":"Char\u985e\u578b\u6578\u64da\u5eab\u5b57\u6bb5\u7684\u6709\u6548\u5224\u65b7\u65b9\u6cd5\u89e3\u6790 (\u5982\u4f55\u5224\u65b7char\u6709\u6548\u6578\u64da\u5eab)"},"content":{"rendered":"

Char\u985e\u578b\u6578\u64da\u5eab\u5b57\u6bb5\u7684\u6709\u6548\u5224\u65b7\u65b9\u6cd5\u89e3\u6790<\/h1>\n

\u5728\u6578\u64da\u5eab\u8a2d\u8a08\u4e2d\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u985e\u578b\u5c0d\u65bc\u6578\u64da\u7684\u5b58\u5132\u548c\u67e5\u8a62\u6548\u7387\u81f3\u95dc\u91cd\u8981\u3002\u7279\u5225\u662f\u5c0d\u65bc\u5b57\u7b26\u985e\u578b\u7684\u6578\u64da\uff0c\u4f7f\u7528 CHAR<\/code> \u985e\u578b\u5b57\u6bb5\u6642\uff0c\u5982\u4f55\u6709\u6548\u5224\u65b7\u5176\u6709\u6548\u6027\u6210\u70ba\u4e86\u4e00\u500b\u91cd\u8981\u7684\u8ab2\u984c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e CHAR<\/code> \u985e\u578b\u6578\u64da\u5eab\u5b57\u6bb5\u7684\u6709\u6548\u5224\u65b7\u65b9\u6cd5\uff0c\u5e6b\u52a9\u958b\u767c\u8005\u66f4\u597d\u5730\u7406\u89e3\u548c\u61c9\u7528\u9019\u4e00\u6578\u64da\u985e\u578b\u3002<\/p>\n

\u4ec0\u9ebc\u662fCHAR\u985e\u578b<\/h2>\n

CHAR<\/code> \u985e\u578b\u662f\u4e00\u7a2e\u56fa\u5b9a\u9577\u5ea6\u7684\u5b57\u7b26\u6578\u64da\u985e\u578b\uff0c\u901a\u5e38\u7528\u65bc\u5b58\u5132\u9577\u5ea6\u76f8\u540c\u7684\u5b57\u7b26\u4e32\u3002\u8207 VARCHAR<\/code> \u985e\u578b\u4e0d\u540c\uff0cCHAR<\/code> \u985e\u578b\u5728\u5b58\u5132\u6642\u6703\u81ea\u52d5\u586b\u5145\u7a7a\u683c\u4ee5\u9054\u5230\u6307\u5b9a\u7684\u9577\u5ea6\u3002\u9019\u4f7f\u5f97 CHAR<\/code> \u985e\u578b\u5728\u8655\u7406\u56fa\u5b9a\u9577\u5ea6\u7684\u6578\u64da\u6642\u66f4\u70ba\u9ad8\u6548\uff0c\u4f46\u5728\u5b58\u5132\u8b8a\u9577\u5b57\u7b26\u4e32\u6642\u5247\u53ef\u80fd\u6d6a\u8cbb\u7a7a\u9593\u3002<\/p>\n

\u6709\u6548\u5224\u65b7CHAR\u985e\u578b\u6578\u64da\u7684\u65b9\u6cd5<\/h2>\n

\u5728\u4f7f\u7528 CHAR<\/code> \u985e\u578b\u5b57\u6bb5\u6642\uff0c\u6709\u6548\u5224\u65b7\u6578\u64da\u7684\u6709\u6548\u6027\u662f\u78ba\u4fdd\u6578\u64da\u5b8c\u6574\u6027\u7684\u91cd\u8981\u6b65\u9a5f\u3002\u4ee5\u4e0b\u662f\u5e7e\u7a2e\u5e38\u7528\u7684\u65b9\u6cd5\uff1a<\/p>\n

1. \u6aa2\u67e5\u9577\u5ea6<\/h3>\n

\u7531\u65bc CHAR<\/code> \u985e\u578b\u5b57\u6bb5\u7684\u9577\u5ea6\u662f\u56fa\u5b9a\u7684\uff0c\u56e0\u6b64\u9996\u5148\u9700\u8981\u6aa2\u67e5\u8f38\u5165\u6578\u64da\u7684\u9577\u5ea6\u662f\u5426\u7b26\u5408\u8981\u6c42\u3002\u53ef\u4ee5\u4f7f\u7528 SQL \u7684 LENGTH()<\/code> \u51fd\u6578\u4f86\u9032\u884c\u5224\u65b7\u3002\u4f8b\u5982\uff1a<\/p>\n

SELECT * FROM your_table WHERE LENGTH(your_char_field) = 10;<\/code><\/pre>\n
\u9019\u689d\u67e5\u8a62\u5c07\u8fd4\u56de\u6240\u6709 your_char_field<\/code> \u9577\u5ea6\u70ba 10 \u7684\u8a18\u9304\u3002<\/p>\n
2. \u6aa2\u67e5\u7a7a\u683c<\/h3>\n
\u7531\u65bc CHAR<\/code> \u985e\u578b\u6703\u81ea\u52d5\u586b\u5145\u7a7a\u683c\uff0c\u56e0\u6b64\u5728\u9032\u884c\u6709\u6548\u6027\u5224\u65b7\u6642\uff0c\u9700\u8981\u8003\u616e\u5230\u7a7a\u683c\u7684\u5f71\u97ff\u3002\u53ef\u4ee5\u4f7f\u7528 TRIM()<\/code> \u51fd\u6578\u4f86\u53bb\u9664\u5b57\u7b26\u4e32\u5169\u7aef\u7684\u7a7a\u683c\uff0c\u7136\u5f8c\u518d\u9032\u884c\u5224\u65b7\uff1a<\/p>\n
SELECT * FROM your_table WHERE TRIM(your_char_field) != '';<\/code><\/pre>\n
\u9019\u6a23\u53ef\u4ee5\u904e\u6ffe\u6389\u6240\u6709\u53ea\u5305\u542b\u7a7a\u683c\u7684\u8a18\u9304\u3002<\/p>\n
3. \u4f7f\u7528\u6b63\u5247\u8868\u9054\u5f0f<\/h3>\n
\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u53ef\u80fd\u9700\u8981\u5c0d CHAR<\/code> \u985e\u578b\u5b57\u6bb5\u7684\u5167\u5bb9\u9032\u884c\u66f4\u70ba\u8907\u96dc\u7684\u6709\u6548\u6027\u6aa2\u67e5\u3002\u9019\u6642\u53ef\u4ee5\u4f7f\u7528\u6b63\u5247\u8868\u9054\u5f0f\u4f86\u9032\u884c\u5339\u914d\u3002\u4f8b\u5982\uff0c\u5982\u679c\u9700\u8981\u6aa2\u67e5\u5b57\u6bb5\u662f\u5426\u53ea\u5305\u542b\u5b57\u6bcd\u548c\u6578\u5b57\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u67e5\u8a62\uff1a<\/p>\n
SELECT * FROM your_table WHERE your_char_field REGEXP '^[A-Za-z0-9]+$';<\/code><\/pre>\n
4. \u6578\u64da\u5b8c\u6574\u6027\u7d04\u675f<\/h3>\n
\u5728\u6578\u64da\u5eab\u8a2d\u8a08\u968e\u6bb5\uff0c\u53ef\u4ee5\u901a\u904e\u8a2d\u7f6e\u7d04\u675f\u4f86\u78ba\u4fdd CHAR<\/code> \u985e\u578b\u5b57\u6bb5\u7684\u6709\u6548\u6027\u3002\u4f8b\u5982\uff0c\u53ef\u4ee5\u4f7f\u7528 NOT NULL<\/code> \u7d04\u675f\u4f86\u9632\u6b62\u7a7a\u503c\u7684\u63d2\u5165\uff1a<\/p>\n
CREATE TABLE your_table (\n    your_char_field CHAR(10) NOT NULL\n);<\/code><\/pre>\n
\u7d50\u8ad6<\/h2>\n
\u6709\u6548\u5224\u65b7 CHAR<\/code> \u985e\u578b\u6578\u64da\u5eab\u5b57\u6bb5\u7684\u6709\u6548\u6027\u662f\u78ba\u4fdd\u6578\u64da\u5b8c\u6574\u6027\u548c\u67e5\u8a62\u6548\u7387\u7684\u91cd\u8981\u6b65\u9a5f\u3002\u901a\u904e\u6aa2\u67e5\u9577\u5ea6\u3001\u53bb\u9664\u7a7a\u683c\u3001\u4f7f\u7528\u6b63\u5247\u8868\u9054\u5f0f\u4ee5\u53ca\u8a2d\u7f6e\u6578\u64da\u5b8c\u6574\u6027\u7d04\u675f\uff0c\u958b\u767c\u8005\u53ef\u4ee5\u66f4\u597d\u5730\u7ba1\u7406\u548c\u4f7f\u7528 CHAR<\/code> \u985e\u578b\u5b57\u6bb5\u3002\u9019\u4e9b\u65b9\u6cd5\u4e0d\u50c5\u80fd\u63d0\u9ad8\u6578\u64da\u7684\u6e96\u78ba\u6027\uff0c\u9084\u80fd\u63d0\u5347\u6574\u9ad4\u7cfb\u7d71\u7684\u6027\u80fd\u3002<\/p>\n
\u5982\u9700\u4e86\u89e3\u66f4\u591a\u95dc\u65bc \u9999\u6e2fVPS<\/a> \u53ca\u5176\u4ed6\u6578\u64da\u5eab\u7ba1\u7406\u7684\u8cc7\u8a0a\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
\u63a2\u7d22Char\u985e\u578b\u6578\u64da\u5eab\u5b57\u6bb5\u7684\u6709\u6548\u5224\u65b7\u65b9\u6cd5\uff0c\u4e86\u89e3\u5982\u4f55\u78ba\u4fdd\u6578\u64da\u6e96\u78ba\u6027\u8207\u4e00\u81f4\u6027\u3002<\/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-59579","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/59579","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=59579"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/59579\/revisions"}],"predecessor-version":[{"id":59580,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/59579\/revisions\/59580"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=59579"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=59579"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=59579"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}