{"id":457,"date":"2010-06-17T18:48:00","date_gmt":"2010-06-17T18:48:00","guid":{"rendered":""},"modified":"2010-06-17T18:48:00","modified_gmt":"2010-06-17T18:48:00","slug":"457","status":"publish","type":"post","link":"https:\/\/www.poloo.org\/?p=457","title":{"rendered":"MySQL\u8bed\u53e5\u4f18\u5316\u7684\u539f\u5219\u7b80\u8ff0"},"content":{"rendered":"

\u4f7f\u7528\u7d22\u5f15\u6765\u66f4\u5feb\u5730\u904d\u5386\u8868\u3002 <\/strong><\/p>\n

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\u5408\u7406\u7684\u7d22\u5f15\u8bbe\u8ba1\u8981\u5efa\u7acb\u5728\u5bf9\u5404\u79cd\u67e5\u8be2\u7684\u5206\u6790\u548c\u9884\u6d4b\u4e0a\u3002\u4e00\u822c\u6765\u8bf4\uff1a<\/p>\n

a.\u6709\u5927\u91cf\u91cd\u590d\u503c\u3001\u4e14\u7ecf\u5e38\u6709\u8303\u56f4\u67e5\u8be2\uff08 > ,< \uff0c> =,< =\uff09\u548corder by\u3001group by\u53d1\u751f\u7684\u5217\uff0c\u53ef\u8003\u8651\u5efa\u7acb\u7fa4\u96c6\u7d22\u5f15\uff1b<\/p>\n

b.\u7ecf\u5e38\u540c\u65f6 \u5b58\u53d6\u591a\u5217\uff0c\u4e14\u6bcf\u5217\u90fd\u542b\u6709\u91cd\u590d\u503c\u53ef\u8003\u8651\u5efa\u7acb\u7ec4\u5408\u7d22\u5f15\uff1b<\/p>\n

c.\u7ec4\u5408\u7d22\u5f15\u8981\u5c3d\u91cf\u4f7f\u5173\u952e\u67e5\u8be2\u5f62\u6210\u7d22\u5f15\u8986\u76d6\uff0c\u5176\u524d\u5bfc\u5217\u4e00\u5b9a\u662f\u4f7f\u7528\u6700\u9891\u7e41\u7684\u5217\u3002\u7d22\u5f15\u867d\u6709\u52a9\u4e8e\u63d0\u9ad8\u6027\u80fd\u4f46\u4e0d\u662f\u7d22\u5f15<\/p>\n

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2\u3001 \u5728\u6d77\u91cf\u67e5\u8be2\u65f6\u5c3d\u91cf\u5c11\u7528\u683c\u5f0f\u8f6c\u6362\u3002<\/p>\n

3\u3001ORDER BY\u548cGROPU BY\u4f7f\u7528ORDER BY\u548cGROUP BY\u77ed\u8bed\uff0c\u4efb\u4f55\u4e00\u79cd\u7d22\u5f15\u90fd\u6709\u52a9\u4e8eSelect\u7684\u6027\u80fd\u63d0\u9ad8\u3002<\/p>\n

4\u3001\u4efb\u4f55\u5bf9\u5217\u7684\u64cd\u4f5c\u90fd\u5c06\u5bfc\u81f4\u8868\u626b\u63cf\uff0c\u5b83\u5305\u62ec\u6570\u636e\u5e93\u51fd\u6570\u3001\u8ba1\u7b97\u8868\u8fbe\u5f0f\u7b49\u7b49\uff0c\u67e5\u8be2\u65f6\u8981\u5c3d\u53ef\u80fd\u5c06\u64cd\u4f5c\u79fb\u81f3\u7b49\u53f7\u53f3\u8fb9\u3002<\/p>\n

5\u3001IN\u3001OR\u5b50\u53e5\u5e38\u4f1a\u4f7f\u7528\u5de5\u4f5c\u8868\uff0c\u4f7f\u7d22\u5f15\u5931\u6548\u3002\u5982\u679c\u4e0d\u4ea7\u751f\u5927\u91cf\u91cd\u590d\u503c\uff0c\u53ef\u4ee5\u8003\u8651\u628a\u5b50\u53e5\u62c6\u5f00\u3002\u62c6\u5f00\u7684\u5b50 \u53e5\u4e2d\u5e94\u8be5\u5305\u542b\u7d22\u5f15\u3002<\/p>\n

6\u3001\u53ea\u8981\u80fd\u6ee1\u8db3\u4f60\u7684\u9700\u6c42\uff0c\u5e94\u5c3d\u53ef\u80fd\u4f7f\u7528\u66f4\u5c0f\u7684\u6570\u636e\u7c7b\u578b\uff1a\u4f8b\u5982\u4f7f\u7528MEDIUMINT\u4ee3\u66ffINT<\/p>\n

7\u3001 \u5c3d\u91cf\u628a\u6240\u6709\u7684\u5217\u8bbe\u7f6e\u4e3aNOT NULL\uff0c\u5982\u679c\u4f60\u8981\u4fdd\u5b58NULL\uff0c\u624b\u52a8\u53bb\u8bbe\u7f6e\u5b83\uff0c\u800c\u4e0d\u662f\u628a\u5b83\u8bbe\u4e3a\u9ed8\u8ba4\u503c\u3002<\/p>\n

8\u3001\u5c3d\u91cf\u5c11\u7528VARCHAR\u3001 TEXT\u3001BLOB\u7c7b\u578b<\/p>\n

9\u3001\u5982\u679c\u4f60\u7684\u6570\u636e\u53ea\u6709\u4f60\u6240\u77e5\u7684\u5c11\u91cf\u7684\u51e0\u4e2a\u3002\u6700\u597d\u4f7f\u7528ENUM\u7c7b\u578b<\/p>\n

10\u3001\u6b63\u5982graymice \u6240\u8bb2\u7684\u90a3\u6837\uff0c\u5efa\u7acb\u7d22\u5f15\u3002<\/p>\n

\u4ee5\u4e0b\u662f\u6211\u505a\u7684\u4e00\u4e2a\u5b9e\u9a8c\uff0c\u53ef\u4ee5\u53d1\u73b0\u7d22\u5f15\u80fd\u6781\u5927\u5730\u63d0\u9ad8\u67e5\u8be2\u7684\u6548\u7387\uff08\u6211\u6709\u4e00\u4e2a\u4f1a\u5458\u4fe1\u606f\u8868users\uff0c\u91cc\u8fb9\u670937365 \u6761\u7528\u6237\u8bb0\u5f55\uff09<\/p>\n

\u5728\u4e0d\u52a0\u7d22\u5f15\u7684\u65f6\u5019\u8fdb\u884c\u67e5\u8be2\uff1a<\/p>\n

sql\u8bed\u53e5A:<\/p>\n


select * from users where username like '%\u8bb8%';  
<\/code>
\u5728Mysql-Front\u4e2d\u76848\u6b21\u67e5\u8be2\u65f6\u957f \u4e3a\uff1a1.40,0.54,0.54,0.54,0.53,0.55,0.54 \u5171\u627e\u5230960\u6761\u8bb0\u5f55<\/p>\n

sql\u8bed\u53e5B:<\/p>\n


select * from users where username like '\u8bb8%';  
<\/code>
\u5728Mysql-Front\u4e2d\u76848\u6b21\u67e5\u8be2\u65f6\u957f \u4e3a\uff1a0.53,0.53,0.53,0.54,0.53,0.53,0.54,0.54 \u5171\u627e\u5230836\u6761\u8bb0\u5f55<\/p>\n

sql\u8bed\u53e5C:<\/p>\n


select * from users where username like '%\u8bb8';  
<\/code>
\u5728Mysql-Front\u4e2d\u76848\u6b21\u67e5\u8be2\u65f6\u957f \u4e3a\uff1a0.51,0.51,0.52,0.52,0.51,0.51,0.52,0.51 \u5171\u627e\u52307\u6761\u8bb0\u5f55<\/p>\n

\u4e3ausername\u5217\u6dfb\u52a0\u7d22 \u5f15:<\/p>\n


create index usernameindex on users(username(6));  
<\/code>
\u518d\u6b21\u67e5\u8be2\uff1a<\/p>\n

sql \u8bed\u53e5A:<\/p>\n


select * from users where username like '%\u8bb8%';  
<\/code>
\u5728Mysql-Front \u4e2d\u76848\u6b21\u67e5\u8be2\u65f6\u957f\u4e3a\uff1a0.35,0.34,0.34,0.35,0.34,0.34,0.35,0.34 \u5171\u627e\u5230960\u6761\u8bb0\u5f55<\/p>\n

sql\u8bed \u53e5B:<\/p>\n


select * from users where username like '\u8bb8%';  
<\/code>
\u5728Mysql-Front\u4e2d\u7684 8\u6b21\u67e5\u8be2\u65f6\u957f\u4e3a\uff1a0.06,0.07,0.07,0.07,0.07,0.07,0.06,0.06 \u5171\u627e\u5230836\u6761\u8bb0\u5f55<\/p>\n

sql\u8bed\u53e5 C:<\/p>\n


select * from users where username like '%\u8bb8';  
<\/code>
\u5728Mysql-Front\u4e2d\u76848 \u6b21\u67e5\u8be2\u65f6\u957f\u4e3a\uff1a0.32,0.31,0.31,0.32,0.31,0.32,0.31,0.31 \u5171\u627e\u52307\u6761\u8bb0\u5f55<\/p>\n

\u5728\u5b9e\u9a8c\u8fc7\u7a0b\u4e2d\uff0c\u6211\u6ca1\u6709 \u53e6\u5f00\u4efb\u4f55\u7a0b\u5e8f\uff0c\u4ee5\u4e0a\u7684\u6570\u636e\u8bf4\u660e\u5728\u5355\u8868\u67e5\u8be2\u4e2d\uff0c\u5efa\u7acb\u7d22\u5f15\u7684\u53ef\u4ee5\u6781\u5927\u5730\u63d0\u9ad8\u67e5\u8be2\u901f\u5ea6\u3002<\/p>\n

\u53e6\u5916\u8981\u8bf4\u7684\u662f\u5982\u679c\u5efa\u7acb\u4e86\u7d22\u5f15\uff0c\u5bf9\u4e8elike ‘\u8bb8%’\u7c7b\u578b\u7684\u67e5\u8be2\uff0c\u901f\u5ea6\u63d0\u5347\u662f\u6700\u660e\u663e\u7684\u3002\u56e0\u6b64\uff0c\u6211\u4eec\u5728\u5199sql\u8bed\u53e5\u7684<\/p>\n

\u65f6\u5019\u4e5f\u5c3d\u91cf\u91c7\u7528\u8fd9\u79cd\u65b9\u5f0f\u67e5\u8be2\u3002 ———–like \u8bed\u53e5\u7684\u5199\u6cd5———-<\/p>\n

\u5bf9\u4e8e\u591a\u8868\u67e5\u8be2\u6211\u4eec\u7684MySQL\u8bed\u53e5\u4f18\u5316\u539f\u5219\u662f\uff1a<\/strong><\/p>\n

\u5c3d\u91cf\u5c06\u7d22\u5f15\u5efa\u7acb\u5728\uff1aleft join on\/right join on …\u3000\uff0b\u6761\u4ef6\uff0c\u7684\u6761\u4ef6\u8bed\u53e5\u4e2d\u6240\u6d89\u53ca\u7684\u5b57\u6bb5\u4e0a\u3002\u591a\u8868\u67e5\u8be2\u6bd4\u5355\u8868\u67e5<\/p>\n

\u8be2\u66f4\u80fd\u4f53\u73b0\u7d22\u5f15\u7684\u4f18\u52bf\u3002<\/p>\n

11\u3001\u7d22\u5f15\u7684\u5efa\u7acb\u539f\u5219\uff1a<\/p>\n

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\u5f15\u65b9\u6cd5\u5c31\u662f\u5bf9username\u6700\u5de6 \u8fb9\u76846\u4e2a\u5b57\u7b26\u8fdb\u884c\u7d22\u5f15\u3002\u7d22\u5f15\u8d8a\u77ed\uff0c\u5360\u7528\u7684 \u78c1\u76d8\u7a7a\u95f4\u8d8a\u5c11\uff0c\u5728\u68c0\u7d22\u8fc7\u7a0b\u4e2d\u82b1\u7684\u65f6<\/p>\n

\u95f4\u4e5f\u8d8a\u5c11\u3002\u8fd9\u65b9\u6cd5\u53ef\u4ee5\u5bf9\u6700\u591a\u5de6255\u4e2a\u5b57\u7b26\u8fdb\u884c\u7d22\u5f15\u3002\uff08\u524d\u7f00\u7d22\u5f15\uff09<\/p>\n

\u5728\u5f88\u591a\u573a\u5408\uff0c\u6211\u4eec\u53ef\u4ee5\u7ed9\u5efa\u7acb\u591a\u5217\u6570\u636e\u5efa\u7acb\u7d22\u5f15\u3002<\/p>\n

\u7d22\u5f15\u5e94\u8be5\u5efa\u7acb\u5728\u67e5\u8be2\u6761\u4ef6\u4e2d\u8fdb\u884c\u6bd4\u8f83\u7684\u5b57\u6bb5\u4e0a\uff0c\u800c\u4e0d\u662f\u5efa\u7acb\u5728\u6211\u4eec\u8981\u627e\u51fa\u6765\u5e76\u4e14\u663e\u793a\u7684\u5b57\u6bb5\u4e0a<\/p>\n

12\u3001 \u4e00\u5f80\u60c5\u6df1\u95ee\u5230\u7684\u95ee\u9898<\/p>\n

IN\u3001OR\u5b50\u53e5\u5e38\u4f1a\u4f7f\u7528\u5de5\u4f5c\u8868\uff0c\u4f7f\u7d22\u5f15\u5931\u6548\u3002\u5982\u679c\u4e0d\u4ea7\u751f\u5927\u91cf\u91cd\u590d\u503c\uff0c\u53ef\u4ee5\u8003\u8651\u628a\u5b50\u53e5\u62c6\u5f00\u3002\u62c6\u5f00\u7684\u5b50\u53e5\u4e2d\u5e94\u8be5\u5305\u542b\u7d22\u5f15\u3002<\/p>\n

\u8fd9 \u53e5\u8bdd\u600e\u4e48\u7406\u89e3\u51b3\uff0c\u8bf7\u4e3e\u4e2a\u4f8b\u5b50<\/p>\n

\u5982\u4e0b:<\/p>\n

\u5982\u679c\u5728fields1\u548cfields2\u4e0a\u540c\u65f6\u5efa\u7acb\u4e86\u7d22\u5f15\uff0cfields1\u4e3a\u4e3b\u7d22\u5f15<\/p>\n

\u4ee5 \u4e0bsql\u4f1a\u7528\u5230\u7d22\u5f15<\/p>\n


select * from tablename1 where fields1='value1' and fields2='value2'
<\/code>
\u4ee5\u4e0bsql\u4e0d\u4f1a\u7528\u5230\u7d22\u5f15<\/p>\n


select * from tablename1 where fields1='value1' or fields2='value2' 13.\u7d22\u5f15\u5e26\u6765\u67e5\u8be2\u4e0a\u7684\u901f\u5ea6\u7684\u5927\u5927\u63d0\u5347,\u4f46\u7d22\u5f15<\/code>
\u4e5f\u5360\u7528\u4e86\u989d\u5916\u7684\u786c\u76d8\u7a7a \u95f4(\u5f53\u7136\u73b0\u5728\u4e00\u822c\u786c\u76d8\u7a7a\u95f4\u4e0d\u6210\u95ee\u9898),<\/p>\n

\u800c\u4e14\u5f80\u8868\u4e2d\u63d2\u5165\u65b0\u8bb0\u5f55\u65f6\u7d22\u5f15\u4e5f\u8981\u968f\u7740\u66f4\u65b0\u8fd9\u4e5f\u9700\u8981\u4e00\u5b9a\u65f6\u95f4.<\/p>\n

\u6709\u4e9b\u8868\u5982\u679c\u7ecf\u5e38insert,\u800c \u8f83\u5c11select,\u5c31\u4e0d\u7528\u52a0\u7d22\u5f15\u4e86.\u4e0d\u7136\u6bcf\u6b21\u5199\u5165\u6570\u636e\u90fd\u8981\u91cd\u65b0\u6539\u5199\u7d22\u5f15,\u82b1\u8d39\u65f6\u95f4; \u8fd9\u4e2a\u89c6<\/p>\n

\u5b9e\u9645\u60c5\u51b5\u800c\u5b9a,\u901a\u5e38\u60c5\u51b5\u4e0b\u7d22\u5f15\u662f\u5fc5\u9700\u7684.<\/p>\n

14. \u6211\u5728\u5bf9\u67e5\u8be2\u6548\u7387\u6709\u6000\u7591\u7684\u65f6\u5019,\u4e00\u822c\u662f\u76f4\u63a5\u7528Mysql\u7684Explain\u6765\u8ddf\u8e2a\u67e5\u8be2\u60c5\u51b5.<\/p>\n

\u4f60\u7528Mysql-Front\u662f\u901a\u8fc7\u65f6\u957f\u6765\u6bd4\u8f83,\u4e0d\u51c6\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

\u4f7f\u7528\u7d22\u5f15\u6765\u66f4\u5feb\u5730\u904d\u5386\u8868\u3002 \u7f3a\u7701\u60c5\u51b5\u4e0b\u5efa\u7acb\u7684\u7d22\u5f15\u662f\u975e\u7fa4\u96c6\u7d22\u5f15\uff0c\u4f46\u6709\u65f6\u5b83...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9],"tags":[],"class_list":["post-457","post","type-post","status-publish","format-standard","hentry","category-DB"],"_links":{"self":[{"href":"https:\/\/www.poloo.org\/index.php?rest_route=\/wp\/v2\/posts\/457","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.poloo.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.poloo.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.poloo.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.poloo.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=457"}],"version-history":[{"count":0,"href":"https:\/\/www.poloo.org\/index.php?rest_route=\/wp\/v2\/posts\/457\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.poloo.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=457"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.poloo.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=457"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.poloo.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=457"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}