{"id":1319,"date":"2024-07-09T14:41:40","date_gmt":"2024-07-09T06:41:40","guid":{"rendered":"https:\/\/blog.nonot.cn\/?p=1319"},"modified":"2024-07-09T14:44:57","modified_gmt":"2024-07-09T06:44:57","slug":"mysql%e8%ae%be%e8%ae%a1%e8%a7%84%e8%8c%83%e5%8f%8asql%e7%b4%a2%e5%bc%95%e4%bc%98%e5%8c%96","status":"publish","type":"post","link":"https:\/\/blog.nonot.cn\/index.php\/2024\/07\/09\/mysql%e8%ae%be%e8%ae%a1%e8%a7%84%e8%8c%83%e5%8f%8asql%e7%b4%a2%e5%bc%95%e4%bc%98%e5%8c%96\/","title":{"rendered":"MySql\u8bbe\u8ba1\u89c4\u8303\u53caSQL\u7d22\u5f15\u4f18\u5316"},"content":{"rendered":"<h2>\u6570\u636e\u5e93\u53ca\u8868\u7ed3\u6784\u57fa\u672c\u8bbe\u8ba1\u89c4\u8303<\/h2>\n<h4>1. \u6240\u6709\u8868\u5fc5\u987b\u4f7f\u7528Innodb\u5b58\u50a8\u5f15\u64ce<\/h4>\n<p>\u6ca1\u6709\u7279\u6b8a\u8981\u6c42\uff08\u5373Innodb\u65e0\u6cd5\u6ee1\u8db3\u7684\u529f\u80fd\u5982\uff1a\u5217\u5b58\u50a8\uff0c\u5b58\u50a8\u7a7a\u95f4\u6570\u636e\u7b49\uff09\u7684\u60c5\u51b5\u4e0b\uff0c\u6240\u6709\u8868\u5fc5\u987b\u4f7f\u7528Innodb\u5b58\u50a8\u5f15\u64ce\uff08mysql5.5\u4e4b\u524d\u9ed8\u8ba4\u4f7f\u7528Myisam\uff0c5.6\u4ee5\u540e\u9ed8\u8ba4\u7684\u4e3aInnodb\uff09\u3002Innodb \u652f\u6301\u4e8b\u52a1\uff0c\u652f\u6301\u884c\u7ea7\u9501\uff0c\u66f4\u597d\u7684\u6062\u590d\u6027\uff0c\u9ad8\u5e76\u53d1\u4e0b\u6027\u80fd\u66f4\u597d\u3002<\/p>\n<h4>2. \u4f18\u5148\u9009\u62e9\u7b26\u5408\u5b58\u50a8\u9700\u8981\u7684\u6700\u5c0f\u7684\u6570\u636e\u7c7b\u578b<\/h4>\n<p>\u5217\u7684\u5b57\u6bb5\u8d8a\u5927\uff0c\u5efa\u7acb\u7d22\u5f15\u65f6\u6240\u9700\u8981\u7684\u7a7a\u95f4\u4e5f\u5c31\u8d8a\u5927\uff0c\u7d22\u5f15\u7684\u6027\u80fd\u4e5f\u8d8a\u5dee\u3002<\/p>\n<h4>3.\u00a0\u5c3d\u53ef\u80fd\u628a\u6240\u6709\u5217\u5b9a\u4e49\u4e3aNOT NULL<\/h4>\n<p>\u7d22\u5f15NULL\u5217\u9700\u8981\u989d\u5916\u7684\u7a7a\u95f4\u6765\u4fdd\u5b58\uff0c\u6240\u4ee5\u8981\u5360\u7528\u66f4\u591a\u7684\u7a7a\u95f4<\/p>\n<p>\u8fdb\u884c\u6bd4\u8f83\u548c\u8ba1\u7b97\u65f6\u8981\u5bf9NULL\u503c\u505a\u7279\u522b\u7684\u5904\u7406<\/p>\n<h4>4. \u4f7f\u7528TIMESTAMP\uff084\u4e2a\u5b57\u8282\uff09\u6216DATETIME\u7c7b\u578b\uff088\u4e2a\u5b57\u8282\uff09\u5b58\u50a8\u65f6\u95f4<\/h4>\n<p>TIMESTAMP \u5b58\u50a8\u7684\u65f6\u95f4\u8303\u56f4 1970-01-01 00:00:01 ~ 2038-01-19-03:14:07\uff0cTIMESTAMP \u5360\u75284\u5b57\u8282\u548cINT\u76f8\u540c\uff0c\u4f46\u6bd4INT\u53ef\u8bfb\u6027\u9ad8\uff1b<\/p>\n<p>\u8d85\u51faTIMESTAMP\u53d6\u503c\u8303\u56f4\u7684\u4f7f\u7528DATETIME\u7c7b\u578b\u5b58\u50a8<\/p>\n<p><strong>\u3000\u3000\u7ecf\u5e38\u4f1a\u6709\u4eba\u7528\u5b57\u7b26\u4e32\u5b58\u50a8\u65e5\u671f\u578b\u7684\u6570\u636e\uff08\u4e0d\u6b63\u786e\u7684\u505a\u6cd5\uff09<\/strong><\/p>\n<ul class=\"list-paddingleft-2\">\n<li>\u7f3a\u70b91\uff1a\u65e0\u6cd5\u7528\u65e5\u671f\u51fd\u6570\u8fdb\u884c\u8ba1\u7b97\u548c\u6bd4\u8f83<\/li>\n<li>\u7f3a\u70b92\uff1a\u7528\u5b57\u7b26\u4e32\u5b58\u50a8\u65e5\u671f\u8981\u5360\u7528\u66f4\u591a\u7684\u7a7a\u95f4<\/li>\n<\/ul>\n<h4>5. \u540c\u8d22\u52a1\u76f8\u5173\u7684\u91d1\u989d\u7c7b\u6570\u636e\u5fc5\u987b\u4f7f\u7528decimal\u7c7b\u578b<\/h4>\n<ul class=\"list-paddingleft-2\">\n<li>\u975e\u7cbe\u51c6\u6d6e\u70b9\uff1afloat,double<\/li>\n<li>\u7cbe\u51c6\u6d6e\u70b9\uff1adecimal<\/li>\n<\/ul>\n<p>Decimal\u7c7b\u578b\u4e3a\u7cbe\u51c6\u6d6e\u70b9\u6570\uff0c\u5728\u8ba1\u7b97\u65f6\u4e0d\u4f1a\u4e22\u5931\u7cbe\u5ea6<\/p>\n<p>\u5360\u7528\u7a7a\u95f4\u7531\u5b9a\u4e49\u7684\u5bbd\u5ea6\u51b3\u5b9a\uff0c\u6bcf4\u4e2a\u5b57\u8282\u53ef\u4ee5\u5b58\u50a89\u4f4d\u6570\u5b57\uff0c\u5e76\u4e14\u5c0f\u6570\u70b9\u8981\u5360\u7528\u4e00\u4e2a\u5b57\u8282<\/p>\n<p>\u53ef\u7528\u4e8e\u5b58\u50a8\u6bd4bigint\u66f4\u5927\u7684\u6574\u578b\u6570\u636e<\/p>\n<h4>6. \u6570\u636e\u5e93\u548c\u8868\u7684\u5b57\u7b26\u96c6\u7edf\u4e00\u4f7f\u7528UTF8<\/h4>\n<p>\u517c\u5bb9\u6027\u66f4\u597d\uff0c\u7edf\u4e00\u5b57\u7b26\u96c6\u53ef\u4ee5\u907f\u514d\u7531\u4e8e\u5b57\u7b26\u96c6\u8f6c\u6362\u4ea7\u751f\u7684\u4e71\u7801\uff1b\u5982\u679c\u6709\u5b58\u50a8emoji\u8868\u60c5\u7684\u9700\u8981\uff0c\u91c7\u7528utf8mb4\u5b57\u7b26\u96c6\u3002<\/p>\n<h4>7. \u5c3d\u91cf\u63a7\u5236\u5355\u8868\u6570\u636e\u91cf\u7684\u5927\u5c0f\uff0c\u5efa\u8bae\u63a7\u5236\u5728500\u4e07\u4ee5\u5185\u3002<\/h4>\n<p>500\u4e07\u5e76\u4e0d\u662fMysql\u6570\u636e\u5e93\u7684\u9650\u5236\uff0c\u8fc7\u5927\u4f1a\u9020\u6210\u4fee\u6539\u8868\u7ed3\u6784\uff0c\u5907\u4efd\uff0c\u6062\u590d\u90fd\u4f1a\u6709\u5f88\u5927\u7684\u95ee\u9898\u3002<\/p>\n<p>\u53ef\u4ee5\u7528\u5386\u53f2\u6570\u636e\u5f52\u6863\uff08\u5e94\u7528\u4e8e\u65e5\u5fd7\u6570\u636e\uff09\uff0c\u5206\u5e93\u5206\u8868\uff08\u5e94\u7528\u4e8e\u4e1a\u52a1\u6570\u636e\uff09\u7b49\u624b\u6bb5\u6765\u63a7\u5236\u6570\u636e\u91cf\u5927\u5c0f<\/p>\n<h4>8. \u7981\u6b62\u5728\u8868\u4e2d\u5efa\u7acb\u9884\u7559\u5b57\u6bb5<\/h4>\n<p>\u9884\u7559\u5b57\u6bb5\u7684\u547d\u540d\u5f88\u96be\u505a\u5230\u89c1\u540d\u8bc6\u4e49\u3002\u9884\u7559\u5b57\u6bb5\u65e0\u6cd5\u786e\u8ba4\u5b58\u50a8\u7684\u6570\u636e\u7c7b\u578b\uff0c\u6240\u4ee5\u65e0\u6cd5\u9009\u62e9\u5408\u9002\u7684\u7c7b\u578b\u3002<\/p>\n<p>\u5bf9\u9884\u7559\u5b57\u6bb5\u7c7b\u578b\u7684\u4fee\u6539\uff0c\u4f1a\u5bf9\u8868\u8fdb\u884c\u9501\u5b9a\u3002<\/p>\n<h4>9. \u7981\u6b62\u5728\u6570\u636e\u5e93\u4e2d\u5b58\u50a8\u56fe\u7247\uff0c\u6587\u4ef6\u7b49\u5927\u7684\u4e8c\u8fdb\u5236\u6570\u636e\uff1b\u901a\u5e38\u6587\u4ef6\u5b58\u50a8\u4e8e\u6587\u4ef6\u670d\u52a1\u5668\uff0c\u6570\u636e\u5e93\u53ea\u5b58\u50a8\u6587\u4ef6\u5730\u5740\u4fe1\u606f<\/h4>\n<h4>10.\u00a0\u5c3d\u91cf\u907f\u514d\u4f7f\u7528\u5916\u952e\u7ea6\u675f\uff08\u8fd9\u4e2a\u5404\u6709\u89c1\u89e3\uff0c\u4e0d\u5f3a\u5236\uff09<\/h4>\n<ul class=\"list-paddingleft-2\">\n<li>\u4e0d\u5efa\u8bae\u4f7f\u7528\u5916\u952e\u7ea6\u675f\uff08foreign key\uff09\uff0c\u4f46\u4e00\u5b9a\u8981\u5728\u8868\u4e0e\u8868\u4e4b\u95f4\u7684\u5173\u8054\u952e\u4e0a\u5efa\u7acb\u7d22\u5f15<\/li>\n<li>\u5916\u952e\u4f1a\u5f71\u54cd\u7236\u8868\u548c\u5b50\u8868\u7684\u5199\u64cd\u4f5c\u4ece\u800c\u964d\u4f4e\u6027\u80fd<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p><strong>SQL\u4f18\u5316\u7ec6\u8282\u89c4\u8303\uff1a<\/strong><\/p>\n<p>\u505aMySQL\u4f18\u5316\uff0c\u6211\u4eec\u8981\u5584\u7528EXPLAIN\u67e5\u770bSQL\u6267\u884c\u8ba1\u5212\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-1320\" title=\"1044505-20190409120104971-519880873\" src=\"https:\/\/blog.nonot.cn\/wp-content\/uploads\/replace\/0fb640cfe4ec8371be5c242b3310a19f.jpeg\" alt=\"1044505-20190409120104971-519880873\" width=\"720\" height=\"93\" \/><\/p>\n<ul>\n<li style=\"list-style-type: none;\">\n<ul>\n<li><strong>type\u5217<\/strong><strong>\uff0c<\/strong>\u8fde\u63a5\u7c7b\u578b\u3002\u4e00\u4e2a\u597d\u7684SQL\u8bed\u53e5\u81f3\u5c11\u8981\u8fbe\u5230range\u7ea7\u522b\u3002\u675c\u7edd\u51fa\u73b0all\u7ea7\u522b\u3002<\/li>\n<li><strong>key\u5217\uff0c<\/strong>\u4f7f\u7528\u5230\u7684\u7d22\u5f15\u540d\u3002\u5982\u679c\u6ca1\u6709\u9009\u62e9\u7d22\u5f15\uff0c\u503c\u662fNULL\u3002\u53ef\u4ee5\u91c7\u53d6\u5f3a\u5236\u7d22\u5f15\u65b9\u5f0f\u3002<\/li>\n<li><strong>key_len\u5217\uff0c<\/strong>\u7d22\u5f15\u957f\u5ea6\u3002<\/li>\n<li><strong>rows\u5217\uff0c<\/strong>\u626b\u63cf\u884c\u6570\u3002\u8be5\u503c\u662f\u4e2a\u9884\u4f30\u503c\u3002<\/li>\n<li><strong>extra\u5217\uff0c<\/strong>\u8be6\u7ec6\u8bf4\u660e\u3002\u6ce8\u610f\uff0c\u5e38\u89c1\u7684\u4e0d\u592a\u53cb\u597d\u7684\u503c\uff0c\u5982\u4e0b\uff1aUsing filesort\uff0cUsing temporary\u3002<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>1\u3001<strong>\u5f53\u53ea\u9700\u8981\u4e00\u6761\u6570\u636e\u7684\u65f6\u5019\uff0c\u4f7f\u7528limit 1\uff0c\u4e3a\u4e86\u4f7fEXPLAIN\u4e2dtype\u5217\u8fbe\u5230const\u7c7b\u578b<\/strong><\/p>\n<h4>2.\u3001\u7981\u6b62\u4f7f\u7528SELECT * \u5fc5\u987b\u4f7f\u7528SELECT &lt;\u5b57\u6bb5\u5217\u8868&gt; \u67e5\u8be2\uff1b\u907f\u514d\u6d88\u8017\u66f4\u591a\u7684CPU\u548cIO\u4ee5\u7f51\u7edc\u5e26\u5bbd\u8d44\u6e90<\/h4>\n<h4>3\u3001 \u907f\u514d\u4f7f\u7528JOIN\u5173\u8054\u592a\u591a\u7684\u8868<\/h4>\n<h4>4\u3001 \u51cf\u5c11\u540c\u6570\u636e\u5e93\u7684\u4ea4\u4e92\u6b21\u6570<\/h4>\n<p><strong>5\u3001\u4f7f\u7528\u5408\u7406\u7684\u5206\u9875\u65b9\u5f0f\u4ee5\u63d0\u9ad8\u5206\u9875\u7684\u6548\u7387<\/strong><\/p>\n<p><strong>\u3000\u3000\u3000\u3000\u5982 select id,name from product limit 800000, 20\uff1b\u00a0 \u66ff\u6362\u4e3a\u00a0select id,name from product where id&gt; 800000 limit 20\uff1b<\/strong><\/p>\n<p><strong>6\u3001\u4e0d\u5efa\u8bae\u4f7f\u7528%\u524d\u7f00\u6a21\u7cca\u67e5\u8be2<\/strong><\/p>\n<h4>7\u3001\u5bf9\u5e94\u540c\u4e00\u5217\u8fdb\u884cor\u5224\u65ad\u65f6\uff0c\u4f7f\u7528in\u4ee3\u66ffor<\/h4>\n<p>in \u7684\u503c\u4e0d\u8981\u8d85\u8fc7500\u4e2a\uff0cin \u64cd\u4f5c\u53ef\u4ee5\u66f4\u6709\u6548\u7684\u5229\u7528\u7d22\u5f15\uff0cor\u5927\u591a\u6570\u60c5\u51b5\u4e0b\u5f88\u5c11\u80fd\u5229\u7528\u5230\u7d22\u5f15\u3002\u5f88\u591a\u65f6\u5019\u4f7f\u7528union all\u6216\u8005\u662funion\uff08\u5fc5\u8981\u7684\u65f6\u5019\uff09\u7684\u65b9\u5f0f\u6765\u4ee3\u66ff\u201cor\u201d\u4f1a\u5f97\u5230\u66f4\u597d\u7684\u6548\u679c\u3002<\/p>\n<h4><strong>8\u3001\u5c3d\u91cf\u7528union all\u4ee3\u66ffunion<\/strong><\/h4>\n<h4>9\u3001 WHERE\u4ece\u53e5\u4e2d\u7981\u6b62\u5bf9\u5217\u8fdb\u884c\u51fd\u6570\u8f6c\u6362\u548c\u8ba1\u7b97<\/h4>\n<p>select user_id,user_project from user_base where age*2=36; \u66ff\u6362\u4e3a\u00a0select user_id,user_project from user_base where age=36\/2;<\/p>\n<p><strong>10\u3001\u907f\u514d\u4ea7\u751f\u5927\u4e8b\u52a1\u64cd\u4f5c<\/strong><\/p>\n<h4>11\u3001\u5728\u660e\u663e\u4e0d\u4f1a\u6709\u91cd\u590d\u503c\u65f6\u4f7f\u7528UNION ALL \u800c\u4e0d\u662fUNION<\/h4>\n<ul class=\"list-paddingleft-2\">\n<li>UNION \u4f1a\u628a\u4e24\u4e2a\u7ed3\u679c\u96c6\u7684\u6240\u6709\u6570\u636e\u653e\u5230\u4e34\u65f6\u8868\u4e2d\u540e\u518d\u8fdb\u884c\u53bb\u91cd\u64cd\u4f5c<\/li>\n<li>UNION ALL \u4e0d\u4f1a\u518d\u5bf9\u7ed3\u679c\u96c6\u8fdb\u884c\u53bb\u91cd\u64cd\u4f5c<\/li>\n<\/ul>\n<h2><\/h2>\n<h2>\u7d22\u5f15\u8bbe\u8ba1\u89c4\u8303<\/h2>\n<h4>1. \u9650\u5236\u6bcf\u5f20\u8868\u4e0a\u7684\u7d22\u5f15\u6570\u91cf\uff0c\u5efa\u8bae\u5355\u5f20\u8868\u7d22\u5f15\u4e0d\u8d85\u8fc75\u4e2a<\/h4>\n<p>\u7d22\u5f15\u5e76\u4e0d\u662f\u8d8a\u591a\u8d8a\u597d\uff01\u7d22\u5f15\u53ef\u4ee5\u63d0\u9ad8\u6548\u7387\u540c\u6837\u53ef\u4ee5\u964d\u4f4e\u6548\u7387\u3002<\/p>\n<p>\u7d22\u5f15\u8fc7\u591a\u4f1a\u589e\u52a0mysql\u4f18\u5316\u5668\u751f\u6210\u6267\u884c\u8ba1\u5212\u7684\u65f6\u95f4\uff0c\u540c\u6837\u4f1a\u964d\u4f4e\u67e5\u8be2\u6027\u80fd\u3002<\/p>\n<h4>2.\u00a0<strong>\u5bf9\u4e8e\u8054\u5408\u7d22\u5f15\u6765\u8bf4\uff0c\u8981\u9075\u5b88\u6700\u5de6\u524d\u7f00\u6cd5\u5219<\/strong><\/h4>\n<p>\u5b57\u6bb5\u957f\u5ea6\u5c0f\u3001\u533a\u5206\u5ea6\u6700\u9ad8\u53ca\u4f7f\u7528\u6700\u9891\u7e41\u7684\u5217\u653e\u5728\u8054\u5408\u7d22\u5f15\u7684\u6700\u5de6\u4fa7<\/p>\n<h4>3. \u907f\u514d\u5efa\u7acb\u5197\u4f59\u7d22\u5f15\u548c\u91cd\u590d\u7d22\u5f15\uff08\u589e\u52a0\u4e86\u67e5\u8be2\u4f18\u5316\u5668\u751f\u6210\u6267\u884c\u8ba1\u5212\u7684\u65f6\u95f4\uff09<\/h4>\n<ul class=\"list-paddingleft-2\">\n<li>\u91cd\u590d\u7d22\u5f15\u793a\u4f8b\uff1aprimary key(id)\u3001index(id)\u3001unique index(id)<\/li>\n<li>\u5197\u4f59\u7d22\u5f15\u793a\u4f8b\uff1aindex(a,b,c)\u3001index(a,b)\u3001index(a)<\/li>\n<\/ul>\n<h4>4. \u6bcf\u4e2aInnodb\u8868\u5fc5\u987b\u6709\u4e2a\u4e3b\u952e<\/h4>\n<p>Innodb\u662f\u6309\u7167\u4e3b\u952e\u7d22\u5f15\u7684\u987a\u5e8f\u6765\u7ec4\u7ec7\u8868\u7684<\/p>\n<ul class=\"list-paddingleft-2\">\n<li>\u4e0d\u8981\u4f7f\u7528UUID,MD5,HASH,\u5b57\u7b26\u4e32\u5217\u4f5c\u4e3a\u4e3b\u952e\uff08\u65e0\u6cd5\u4fdd\u8bc1\u6570\u636e\u7684\u987a\u5e8f\u589e\u957f\uff09<\/li>\n<li>\u4e3b\u952e\u5efa\u8bae\u4f7f\u7528\u81ea\u589eID\u503c<\/li>\n<\/ul>\n<h4>5.\u5e38\u89c1\u7d22\u5f15\u5217\u5efa\u8bae<\/h4>\n<ul class=\"list-paddingleft-2\">\n<li>\u51fa\u73b0\u5728SELECT\u3001UPDATE\u3001DELETE\u8bed\u53e5\u7684WHERE\u4ece\u53e5\u4e2d\u7684\u5217<\/li>\n<li>\u5305\u542b\u5728ORDER BY\u3001GROUP BY\u3001DISTINCT\u4e2d\u7684\u5b57\u6bb5<\/li>\n<li>\u5e76\u4e0d\u8981\u5c06\u7b26\u54081\u548c2\u4e2d\u7684\u5b57\u6bb5\u7684\u5217\u90fd\u5efa\u7acb\u4e00\u4e2a\u7d22\u5f15\uff0c \u901a\u5e38\u5c061\u30012\u4e2d\u7684\u5b57\u6bb5\u5efa\u7acb\u8054\u5408\u7d22\u5f15\u6548\u679c\u66f4\u597d<\/li>\n<li>\u591a\u8868join\u7684\u5173\u8054\u5217<\/li>\n<\/ul>\n<p><strong>6\u3001\u6ce8\u610f\u8303\u56f4\u67e5\u8be2\u8bed\u53e5<\/strong><\/p>\n<p>\u5bf9\u4e8e\u8054\u5408\u7d22\u5f15\u6765\u8bf4\uff0c\u5982\u679c\u5b58\u5728\u8303\u56f4\u67e5\u8be2\uff0c\u6bd4\u5982between\u3001&gt;\u3001&lt;\u7b49\u6761\u4ef6\u65f6\uff0c\u4f1a\u9020\u6210\u540e\u9762\u7684\u7d22\u5f15\u5b57\u6bb5\u5931\u6548\u3002<\/p>\n<p><strong>7\u3001\u5c3d\u91cf\u4f7f\u7528inner join\uff0c\u907f\u514dleft join\uff1a\u5229\u7528\u5c0f\u8868\u53bb\u9a71\u52a8\u5927\u8868<\/strong><\/p>\n<p>\u53c2\u4e0e\u8054\u5408\u67e5\u8be2\u7684\u8868\u81f3\u5c11\u4e3a2\u5f20\u8868\uff0c\u4e00\u822c\u90fd\u5b58\u5728\u5927\u5c0f\u4e4b\u5206\u3002\u5982\u679c\u8fde\u63a5\u65b9\u5f0f\u662finner join\uff0c\u5728\u6ca1\u6709\u5176\u4ed6\u8fc7\u6ee4\u6761\u4ef6\u7684\u60c5\u51b5\u4e0bMySQL\u4f1a\u81ea\u52a8\u9009\u62e9\u5c0f\u8868\u4f5c\u4e3a\u9a71\u52a8\u8868\uff0c\u4f46\u662fleft join\u5728\u9a71\u52a8\u8868\u7684\u9009\u62e9\u4e0a\u9075\u5faa\u7684\u662f\u5de6\u8fb9\u9a71\u52a8\u53f3\u8fb9\u7684\u539f\u5219\uff0c\u5373left join\u5de6\u8fb9\u7684\u8868\u540d\u4e3a\u9a71\u52a8\u8868\u3002<\/p>\n<p>8<strong>\u3001\u533a\u5206in\u548cexists\u3001not in\u548cnot exists<\/strong><\/p>\n<p>\u5173\u4e8enot in\u548cnot exists\uff0c\u63a8\u8350\u4f7f\u7528not exists\u3002\u00a0 \u66f4\u591a\u6bd4\u8f83\u79fb\u6b65\uff1a<a id=\"cb_post_title_url\" href=\"https:\/\/www.cnblogs.com\/beijingstruggle\/p\/5885137.html\" rel=\"noopener\">\u6d45\u6790MySQL\u4e2dexists\u4e0ein\u7684\u4f7f\u7528 \uff08\u5199\u7684\u975e\u5e38\u597d\uff09<\/a><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>\u53c2\u8003\u6587\u7ae0\uff1a<\/strong><\/p>\n<p><strong><a id=\"cb_post_title_url\" class=\"postTitle2\" href=\"https:\/\/www.cnblogs.com\/xixibaby\/p\/6409928.html\" rel=\"noopener\">sql\u4e2d\u7d22\u5f15\u4e0d\u4f1a\u88ab\u7528\u5230\u7684\u51e0\u79cd\u60c5\u51b5<\/a><\/strong><\/p>\n<div id=\"main_container\">\n<div id=\"main_content\">\n<div id=\"content\">\n<div id=\"post_detail\">\n<div class=\"post\">\n<h2><a id=\"cb_post_title_url\" href=\"https:\/\/www.cnblogs.com\/beijingstruggle\/p\/5885137.html\" rel=\"noopener\">\u6d45\u6790MySQL\u4e2dexists\u4e0ein\u7684\u4f7f\u7528 \uff08\u5199\u7684\u975e\u5e38\u597d\uff09<\/a><\/h2>\n<h2 id=\"activity-name\" class=\"rich_media_title\"><a href=\"https:\/\/mp.weixin.qq.com\/s\/CzjAlQhH8kGMN3km413KTA\" target=\"_blank\" rel=\"noopener\">Mysql\u9ad8\u6027\u80fd\u4f18\u5316\u89c4\u8303\u5efa\u8bae<\/a><\/h2>\n<h2 id=\"activity-name\" class=\"rich_media_title\"><a href=\"https:\/\/mp.weixin.qq.com\/s\/fXJ-25w7MDUA7O20VX53-w\" target=\"_blank\" rel=\"noopener\">\u5de7\u7528\u8fd919\u6761MySQL\u4f18\u5316\uff0c\u6548\u7387\u81f3\u5c11\u63d0\u9ad83\u500d<\/a><\/h2>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>\u6570\u636e\u5e93\u53ca\u8868\u7ed3\u6784\u57fa\u672c\u8bbe\u8ba1\u89c4\u8303 1. \u6240\u6709\u8868\u5fc5\u987b\u4f7f\u7528Innodb&hellip;<\/p>\n","protected":false},"author":1,"featured_media":1321,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-1319","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mysql"],"_links":{"self":[{"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/posts\/1319","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/comments?post=1319"}],"version-history":[{"count":1,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/posts\/1319\/revisions"}],"predecessor-version":[{"id":1322,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/posts\/1319\/revisions\/1322"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/media\/1321"}],"wp:attachment":[{"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/media?parent=1319"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/categories?post=1319"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.nonot.cn\/index.php\/wp-json\/wp\/v2\/tags?post=1319"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}