{"id":77846,"date":"2024-10-16T11:14:17","date_gmt":"2024-10-16T03:14:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/77846\/"},"modified":"2024-10-16T11:14:17","modified_gmt":"2024-10-16T03:14:17","slug":"mysql%e6%8c%87%e4%bb%a4-char%ef%bc%88%e5%ae%9a%e9%95%b7%e5%ad%97%e7%ac%a6%e4%b8%b2%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/77846\/","title":{"rendered":"MySQL\u6307\u4ee4: CHAR\uff08\u5b9a\u9577\u5b57\u7b26\u4e32\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-char%ef%bc%88%e5%ae%9a%e9%95%b7%e5%ad%97%e7%ac%a6%e4%b8%b2%ef%bc%89-QyXoocZTIz\">MySQL\u6307\u4ee4: CHAR\uff08\u5b9a\u9577\u5b57\u7b26\u4e32\uff09<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u8cc7\u6599\u5eab\u7cfb\u7d71\u3002\u5b83\u63d0\u4f9b\u4e86\u591a\u7a2e\u6578\u64da\u985e\u578b\u4ee5\u6eff\u8db3\u4e0d\u540c\u7684\u9700\u6c42\uff0c\u5176\u4e2d\u4e4b\u4e00\u5c31\u662fCHAR\uff08\u5b9a\u9577\u5b57\u7b26\u4e32\uff09\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eCHAR\u7684\u7279\u6027\u3001\u4f7f\u7528\u60c5\u5883\u53ca\u5176\u8207\u5176\u4ed6\u6578\u64da\u985e\u578b\u7684\u6bd4\u8f03\u3002<\/p>\n<h2 id=\"char%e7%9a%84%e5%9f%ba%e6%9c%ac%e6%a6%82%e5%bf%b5-QyXoocZTIz\">CHAR\u7684\u57fa\u672c\u6982\u5ff5<\/h2>\n<p>CHAR\u662f\u4e00\u7a2e\u5b9a\u9577\u5b57\u7b26\u4e32\u6578\u64da\u985e\u578b\uff0c\u7576\u4f60\u5b9a\u7fa9\u4e00\u500bCHAR\u985e\u578b\u7684\u6b04\u4f4d\u6642\uff0c\u5fc5\u9808\u6307\u5b9a\u5176\u9577\u5ea6\uff08\u7bc4\u570d\u70ba0\u5230255\u500b\u5b57\u7b26\uff09\u3002\u7121\u8ad6\u5be6\u969b\u5b58\u5132\u7684\u5b57\u7b26\u4e32\u9577\u5ea6\u5982\u4f55\uff0cMySQL\u90fd\u6703\u5c07\u5176\u586b\u5145\u5230\u6307\u5b9a\u7684\u9577\u5ea6\u3002\u9019\u610f\u5473\u8457\uff0c\u5982\u679c\u4f60\u5b58\u5132\u7684\u5b57\u7b26\u4e32\u5c11\u65bc\u5b9a\u7fa9\u7684\u9577\u5ea6\uff0cMySQL\u6703\u81ea\u52d5\u5728\u5b57\u7b26\u4e32\u7684\u53f3\u5074\u586b\u5145\u7a7a\u683c\u4ee5\u9054\u5230\u6240\u9700\u7684\u9577\u5ea6\u3002<\/p>\n<h2 id=\"char%e7%9a%84%e4%bd%bf%e7%94%a8%e6%83%85%e5%a2%83-QyXoocZTIz\">CHAR\u7684\u4f7f\u7528\u60c5\u5883<\/h2>\n<p>CHAR\u985e\u578b\u7279\u5225\u9069\u5408\u7528\u65bc\u5b58\u5132\u9577\u5ea6\u56fa\u5b9a\u7684\u6578\u64da\uff0c\u4f8b\u5982\u570b\u5bb6\u4ee3\u78bc\u3001\u6027\u5225\u6a19\u8b58\u7b26\u6216\u5176\u4ed6\u985e\u4f3c\u7684\u6578\u64da\u3002\u7531\u65bcCHAR\u7684\u9577\u5ea6\u662f\u56fa\u5b9a\u7684\uff0c\u9019\u4f7f\u5f97\u5728\u67e5\u8a62\u6642\u7684\u6027\u80fd\u8868\u73fe\u901a\u5e38\u6703\u512a\u65bc\u53ef\u8b8a\u9577\u5ea6\u7684\u6578\u64da\u985e\u578b\uff08\u5982VARCHAR\uff09\u3002<\/p>\n<h3 id=\"char%e7%9a%84%e5%84%aa%e7%bc%ba%e9%bb%9e-QyXoocZTIz\">CHAR\u7684\u512a\u7f3a\u9ede<\/h3>\n<ul>\n<li><strong>\u512a\u9ede\uff1a<\/strong>\n<ul>\n<li>\u67e5\u8a62\u6027\u80fd\u8f03\u597d\uff1a\u7531\u65bc\u9577\u5ea6\u56fa\u5b9a\uff0cMySQL\u5728\u8655\u7406CHAR\u985e\u578b\u7684\u6578\u64da\u6642\u53ef\u4ee5\u66f4\u5feb\u5730\u5b9a\u4f4d\u548c\u6aa2\u7d22\u6578\u64da\u3002<\/li>\n<li>\u7c21\u55ae\u6613\u7528\uff1a\u5c0d\u65bc\u9577\u5ea6\u56fa\u5b9a\u7684\u6578\u64da\uff0c\u4f7f\u7528CHAR\u53ef\u4ee5\u7c21\u5316\u6578\u64da\u7684\u7ba1\u7406\u3002<\/li>\n<\/ul>\n<\/li>\n<li><strong>\u7f3a\u9ede\uff1a<\/strong>\n<ul>\n<li>\u7a7a\u9593\u6d6a\u8cbb\uff1a\u5982\u679c\u5b58\u5132\u7684\u5b57\u7b26\u4e32\u9577\u5ea6\u9060\u5c0f\u65bc\u5b9a\u7fa9\u7684\u9577\u5ea6\uff0c\u5247\u6703\u6d6a\u8cbb\u5b58\u5132\u7a7a\u9593\u3002<\/li>\n<li>\u4e0d\u9748\u6d3b\uff1a\u5c0d\u65bc\u9577\u5ea6\u4e0d\u56fa\u5b9a\u7684\u6578\u64da\uff0c\u4f7f\u7528CHAR\u53ef\u80fd\u6703\u5c0e\u81f4\u4e0d\u5fc5\u8981\u7684\u586b\u5145\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<h2 id=\"char%e8%88%87varchar%e7%9a%84%e6%af%94%e8%bc%83-QyXoocZTIz\">CHAR\u8207VARCHAR\u7684\u6bd4\u8f03<\/h2>\n<p>\u5728MySQL\u4e2d\uff0c\u9664\u4e86CHAR\u4e4b\u5916\uff0c\u9084\u6709\u53e6\u4e00\u500b\u5e38\u7528\u7684\u5b57\u7b26\u4e32\u6578\u64da\u985e\u578b\uff1aVARCHAR\u3002\u9019\u5169\u8005\u4e4b\u9593\u7684\u4e3b\u8981\u5340\u5225\u5728\u65bc\u9577\u5ea6\u7684\u8655\u7406\u65b9\u5f0f\u3002<\/p>\n<ul>\n<li><strong>CHAR\uff1a<\/strong>\u5b9a\u9577\u5b57\u7b26\u4e32\uff0c\u7121\u8ad6\u5be6\u969b\u5b58\u5132\u7684\u6578\u64da\u9577\u5ea6\u5982\u4f55\uff0c\u59cb\u7d42\u4f54\u7528\u56fa\u5b9a\u7684\u7a7a\u9593\u3002<\/li>\n<li><strong>VARCHAR\uff1a<\/strong>\u53ef\u8b8a\u9577\u5b57\u7b26\u4e32\uff0c\u6839\u64da\u5be6\u969b\u5b58\u5132\u7684\u6578\u64da\u9577\u5ea6\u4f54\u7528\u7a7a\u9593\uff0c\u6700\u5927\u9577\u5ea6\u53ef\u905465535\u500b\u5b57\u7b26\uff08\u53d6\u6c7a\u65bc\u884c\u7684\u5176\u4ed6\u5217\u7684\u5927\u5c0f\uff09\u3002<\/li>\n<\/ul>\n<p>\u56e0\u6b64\uff0c\u7576\u4f60\u9700\u8981\u5b58\u5132\u9577\u5ea6\u56fa\u5b9a\u7684\u6578\u64da\u6642\uff0cCHAR\u662f\u66f4\u597d\u7684\u9078\u64c7\uff1b\u800c\u7576\u6578\u64da\u9577\u5ea6\u4e0d\u56fa\u5b9a\u6642\uff0c\u5247\u61c9\u8003\u616e\u4f7f\u7528VARCHAR\u3002<\/p>\n<h2 id=\"char%e7%9a%84%e7%af%84%e4%be%8b-QyXoocZTIz\">CHAR\u7684\u7bc4\u4f8b<\/h2>\n<p>\u4ee5\u4e0b\u662f\u4e00\u500b\u4f7f\u7528CHAR\u985e\u578b\u7684\u7c21\u55ae\u7bc4\u4f8b\uff1a<\/p>\n<pre><code>CREATE TABLE users (\n    id INT AUTO_INCREMENT PRIMARY KEY,\n    country_code CHAR(2) NOT NULL,\n    gender CHAR(1) NOT NULL\n);\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u7bc4\u4f8b\u4e2d\uff0c\u6211\u5011\u5275\u5efa\u4e86\u4e00\u500b\u540d\u70bausers\u7684\u8868\uff0c\u5176\u4e2dcountry_code\u6b04\u4f4d\u7528\u4f86\u5b58\u5132\u5169\u4f4d\u6578\u7684\u570b\u5bb6\u4ee3\u78bc\uff0c\u800cgender\u6b04\u4f4d\u5247\u7528\u4f86\u5b58\u5132\u4e00\u4f4d\u6578\u7684\u6027\u5225\u6a19\u8b58\u7b26\u3002\u9019\u6a23\u7684\u8a2d\u8a08\u78ba\u4fdd\u4e86\u6578\u64da\u7684\u4e00\u81f4\u6027\u548c\u67e5\u8a62\u7684\u9ad8\u6548\u6027\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-QyXoocZTIz\">\u7e3d\u7d50<\/h2>\n<p>CHAR\uff08\u5b9a\u9577\u5b57\u7b26\u4e32\uff09\u5728MySQL\u4e2d\u662f\u4e00\u500b\u91cd\u8981\u7684\u6578\u64da\u985e\u578b\uff0c\u9069\u5408\u7528\u65bc\u5b58\u5132\u9577\u5ea6\u56fa\u5b9a\u7684\u6578\u64da\u3002\u96d6\u7136\u5b83\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\u53ef\u80fd\u6703\u5c0e\u81f4\u7a7a\u9593\u6d6a\u8cbb\uff0c\u4f46\u5728\u67e5\u8a62\u6027\u80fd\u548c\u6578\u64da\u7ba1\u7406\u4e0a\u537b\u6709\u5176\u7368\u7279\u7684\u512a\u52e2\u3002\u4e86\u89e3CHAR\u7684\u7279\u6027\u53ca\u5176\u8207\u5176\u4ed6\u6578\u64da\u985e\u578b\u7684\u6bd4\u8f03\uff0c\u80fd\u5e6b\u52a9\u958b\u767c\u8005\u5728\u8a2d\u8a08\u8cc7\u6599\u5eab\u6642\u505a\u51fa\u66f4\u660e\u667a\u7684\u9078\u64c7\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u95dc\u65bc<code>VPS<\/code>\u3001<code>\u9999\u6e2fvps<\/code>\u3001<code>\u670d\u52a1\u5668<\/code>\u3001<code>\u4e91\u670d\u52a1\u5668<\/code>\u7b49\u8cc7\u8a0a\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9 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