{"id":1522,"date":"2022-11-07T22:47:18","date_gmt":"2022-11-07T14:47:18","guid":{"rendered":"https:\/\/qaqaq.top\/?p=1522"},"modified":"2022-11-27T12:40:59","modified_gmt":"2022-11-27T04:40:59","slug":"5%e5%a4%a7%e5%b8%b8%e7%94%a8%e7%9a%84%e8%81%9a%e5%90%88%e5%87%bd%e6%95%b0%e3%80%81group-by%e7%9a%84%e4%bd%bf%e7%94%a8%e3%80%81having%e7%9a%84%e4%bd%bf%e7%94%a8%e4%b8%8esql%e8%af%ad%e5%8f%a5%e6%89%a7","status":"publish","type":"post","link":"https:\/\/qaqaq.top\/?p=1522","title":{"rendered":"5\u5927\u5e38\u7528\u7684\u805a\u5408\u51fd\u6570\u3001GROUP BY\u7684\u4f7f\u7528\u3001HAVING\u7684\u4f7f\u7528\u4e0eSQL\u8bed\u53e5\u6267\u884c\u8fc7\u7a0b"},"content":{"rendered":"\n<pre class=\"wp-block-code\"><code># \u7b2c08\u7ae0_\u805a\u5408\u51fd\u6570\r\n\r\n# 1. \u5e38\u89c1\u7684\u51e0\u4e2a\u805a\u5408\u51fd\u6570\r\n# 1.1 AVG \\ SUM : \u53ea\u9002\u7528\u4e8e\u6570\u503c\u7c7b\u578b\u7684\u5b57\u6bb5\uff08\u6216\u53d8\u91cf\uff09\r\n\r\nSELECT AVG(salary),SUM(salary),AVG(salary) * 107\r\nFROM employees;\r\n# \u5982\u4e0b\u7684\u64cd\u4f5c\u6ca1\u6709\u610f\u4e49\r\nSELECT SUM(last_name),AVG(last_name),SUM(hire_date)\r\nFROM employees;\r\n\r\n# 1.2 MAX \\ MIN : \u9002\u7528\u4e8e\u6570\u503c\u7c7b\u578b\u3001\u5b57\u7b26\u4e32\u7c7b\u578b\u3001\u65e5\u671f\u65f6\u95f4\u7c7b\u578b\u7684\u5b57\u6bb5\uff08\u6216\u53d8\u91cf\uff09\r\n\r\nSELECT MAX(salary),MIN(salary)\r\nFROM employees;\r\n\r\nSELECT MAX(last_name),MIN(last_name),MAX(hire_date),MIN(hire_date)\r\nFROM employees;\r\n# 1.3 COUNT :\r\n#\u2460 \u4f5c\u7528\uff1a\u8ba1\u7b97\u6307\u5b9a\u5b57\u6bb5\u5728\u67e5\u8be2\u7ed3\u6784\u4e2d\u51fa\u73b0\u7684\u4e2a\u6570\uff08\u4e0d\u5305\u542bNULL\u503c\u7684\uff09\r\n\r\nSELECT COUNT(employee_id),COUNT(salary),COUNT(2 * salary),COUNT(1),COUNT(2),COUNT(*)\r\nFROM employees;\r\n\r\nSELECT *\r\nFROM employees;\r\n\r\n#\u5982\u679c\u8ba1\u7b97\u8868\u4e2d\u6709\u591a\u5c11\u6761\u8bb0\u5f55\uff0c\u5982\u4f55\u5b9e\u73b0\uff1f\r\n#\u65b9\u5f0f1\uff1aCOUNT(*)\r\n#\u65b9\u5f0f2\uff1aCOUNT(1)\r\n#\u65b9\u5f0f3\uff1aCOUNT(\u5177\u4f53\u5b57\u6bb5)  :   \u4e0d\u4e00\u5b9a\u5bf9\uff01\r\n\r\n#\u2461 \u6ce8\u610f\uff1a\u8ba1\u7b97\u6307\u5b9a\u5b57\u6bb5\u51fa\u73b0\u7684\u4e2a\u6570\u65f6\uff0c\u662f\u4e0d\u8ba1\u7b97NULL\u503c\u7684\u3002\r\nSELECT COUNT(commission_pct)\r\nFROM employees;\r\n\r\nSELECT commission_pct\r\nFROM employees\r\nWHERE commission_pct IS NOT NULL;\r\n\r\n#\u2462 \u516c\u5f0f\uff1aAVG = SUM \/ COUNT\r\nSELECT AVG(salary),SUM(salary) \/ COUNT(salary),\r\n       AVG(commission_pct),SUM(commission_pct) \/ COUNT(commission_pct),\r\n       SUM(commission_pct) \/ 107\r\nFROM employees;\r\n\r\n#\u9700\u6c42\uff1a\u67e5\u8be2\u516c\u53f8\u4e2d\u5e73\u5747\u5956\u91d1\u7387\r\nSELECT AVG(commission_pct)\r\nFROM employees;\r\n\r\n#\u6b63\u786e\u7684\uff1a\r\nSELECT SUM(commission_pct) \/ COUNT(IFNULL(commission_pct,0)),\r\nAVG(IFNULL(commission_pct,0))\r\nFROM employees;\r\n\r\n# \u5982\u679c\u9700\u8981\u7edf\u8ba1\u8868\u4e2d\u7684\u8bb0\u5f55\u6570\uff0c\u4f7f\u7528COUNT(*)\u3001COUNT(1)\u3001COUNT(\u5177\u4f53\u5b57\u6bb5) \u54ea\u4e2a\u6548\u7387\u66f4\u9ad8\u5462\uff1f\r\n# \u5982\u679c\u4f7f\u7528\u7684\u662fMyISAM \u5b58\u50a8\u5f15\u64ce\uff0c\u5219\u4e09\u8005\u6548\u7387\u76f8\u540c\uff0c\u90fd\u662fo(1)\r\n# \u5982\u679c\u4f7f\u7528\u7684\u662fInnoDB \u5b58\u50a8\u5f15\u64ce\uff0c\u5219\u4e09\u8005\u6548\u7387\uff1aCOUNT(*) = COUNT(1) > COUNT(\u5b57\u6bb5)\r\n\r\n# \u5176\u4ed6\uff1a\u65b9\u5dee\u3001\u6807\u51c6\u5dee\u3001\u4e2d\u4f4d\u6570\r\n\r\n# 2. GROUP BY \u7684\u4f7f\u7528\r\n\r\n#\u9700\u6c42\uff1a\u67e5\u8be2\u5404\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\uff0c\u6700\u9ad8\u5de5\u8d44\r\nSELECT department_id,AVG(salary),SUM(salary)\r\nFROM employees\r\nGROUP BY department_id\r\n\r\n#\u9700\u6c42\uff1a\u67e5\u8be2\u5404\u4e2ajob_id\u7684\u5e73\u5747\u5de5\u8d44\r\nSELECT job_id, AVG(salary)\r\nFROM employees\r\nGROUP BY job_id;\r\n\r\n#\u9700\u6c42\uff1a\u67e5\u8be2\u5404\u4e2adepartment_id,job_id\u7684\u5e73\u5747\u5de5\u8d44\r\n#\u65b9\u5f0f1\uff1a\r\nSELECT department_id,job_id, AVG(salary)\r\nFROM employees\r\nGROUP BY department_id,job_id;\r\n#\u65b9\u5f0f2\uff1a\r\nSELECT job_id,department_id, AVG(salary)\r\nFROM employees\r\nGROUP BY job_id,department_id;\r\n\r\n#\u9519\u8bef\u7684\uff01\r\nSELECT department_id,job_id,AVG(salary)\r\nFROM employees\r\nGROUP BY department_id;\r\n\r\n# \u7ed3\u8bba1\uff1aSELECT\u4e2d\u51fa\u73b0\u7684\u975e\u7ec4\u51fd\u6570\u7684\u5b57\u6bb5\u5fc5\u987b\u58f0\u660e\u5728GROUP BY \u4e2d\u3002\r\n#        \u53cd\u4e4b\uff0cGROUP BY \u4e2d\u58f0\u660e\u7684\u5b57\u6bb5\u53ef\u4ee5\u4e0d\u51fa\u73b0\u5728SELECT\u4e2d\u3002\r\n\r\n#\u7ed3\u8bba2\uff1aGROUP BY \u58f0\u660e\u5728FROM\u540e\u9762\u3001WHERE\u540e\u9762\u3001ORDER BY \u524d\u9762\u3001LIMIT\u524d\u9762\r\n\r\n#\u7ed3\u8bba3\uff1aMySQL\u4e2dGROUP BY\u4e2d\u4f7f\u7528WITH ROLLUP\r\n\r\nSELECT department_id,AVG(salary)\r\nFROM employees\r\nGROUP BY department_id WITH ROLLUP;\r\n\r\n#\u9700\u6c42\uff1a\u67e5\u8be2\u5404\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u5de5\u8d44\uff0c\u6309\u7167\u5e73\u5747\u5de5\u8d44\u5347\u5e8f\u6392\u5217\r\nSELECT department_id,AVG(salary) AS \"avg_sal\"\r\nFROM employees\r\nGROUP BY department_id\r\nORDER BY avg_sal ASC;\r\n\r\n#\u8bf4\u660e\uff1a\u5728MySQL5.7\u4e2d \u5f53\u4f7f\u7528ROLLUP\u65f6\uff0c\u4e0d\u80fd\u540c\u65f6\u4f7f\u7528ORDER BY\u5b50\u53e5\u8fdb\u884c\u7ed3\u679c\u6392\u5e8f\uff0c\u5373ROLLUP\u548cORDER BY\u662f\u4e92\u76f8\u6392\u65a5\u7684\u3002\r\n#      \u4f46\u662f\u5728MySQL8.0\u4e2d \u53ef\u4ee5\u540c\u65f6\u4f7f\u7528\r\n#\u9519\u8bef\u7684\uff1a\r\nSELECT department_id,AVG(salary) AS \"avg_sal\"\r\nFROM employees\r\nGROUP BY department_id WITH ROLLUP\r\nORDER BY avg_sal ASC;\r\n\r\n# 3. HAVING \u7684\u4f7f\u7528 \uff08\u4f5c\u7528\uff1a\u7528\u6765\u8fc7\u6ee4\u6570\u636e\u7684\uff09\r\n#\u7ec3\u4e60\uff1a\u67e5\u8be2\u5404\u4e2a\u90e8\u95e8\u4e2d\u6700\u9ad8\u5de5\u8d44\u6bd410000\u9ad8\u7684\u90e8\u95e8\u4fe1\u606f\r\n#\u9519\u8bef\u7684\u5199\u6cd5\uff1a\r\nSELECT department_id,MAX(salary)\r\nFROM employees\r\nWHERE MAX(salary) > 10000\r\nGROUP BY department_id;\r\n\r\n#\u8981\u6c421\uff1a\u5982\u679c\u8fc7\u6ee4\u6761\u4ef6\u4e2d\u4f7f\u7528\u4e86\u805a\u5408\u51fd\u6570\uff0c\u5219\u5fc5\u987b\u4f7f\u7528HAVING\u6765\u66ff\u6362WHERE\u3002\u5426\u5219\uff0c\u62a5\u9519\u3002\r\n#\u8981\u6c422\uff1aHAVING \u5fc5\u987b\u58f0\u660e\u5728 GROUP BY \u7684\u540e\u9762\u3002\r\n\r\n#\u6b63\u786e\u7684\u5199\u6cd5\uff1a\r\nSELECT department_id,MAX(salary)\r\nFROM employees\r\nGROUP BY department_id\r\nHAVING MAX(salary) > 10000;\r\n\r\n#\u8981\u6c423\uff1a\u5f00\u53d1\u4e2d\uff0c\u6211\u4eec\u4f7f\u7528HAVING\u7684\u524d\u63d0\u662fSQL\u4e2d\u4f7f\u7528\u4e86GROUP BY\u3002\r\n\r\n#\u7ec3\u4e60\uff1a\u67e5\u8be2\u90e8\u95e8id\u4e3a10,20,30,40\u8fd94\u4e2a\u90e8\u95e8\u4e2d\u6700\u9ad8\u5de5\u8d44\u6bd410000\u9ad8\u7684\u90e8\u95e8\u4fe1\u606f\r\n#\u65b9\u5f0f1\uff1a\u63a8\u8350\uff0c\u6267\u884c\u6548\u7387\u9ad8\u4e8e\u65b9\u5f0f2.\r\nSELECT department_id,MAX(salary)\r\nFROM employees\r\nWHERE department_id IN (10,20,30,40)\r\nGROUP BY department_id\r\nHAVING MAX(salary) > 10000;\r\n\r\n#\u65b9\u5f0f2\uff1a\r\nSELECT department_id,MAX(salary)\r\nFROM employees\r\nGROUP BY department_id\r\nHAVING MAX(salary) > 10000 AND department_id IN (10,20,30,40);\r\n\r\n#\u7ed3\u8bba\uff1a\u5f53\u8fc7\u6ee4\u6761\u4ef6\u4e2d\u6709\u805a\u5408\u51fd\u6570\u65f6\uff0c\u5219\u6b64\u8fc7\u6ee4\u6761\u4ef6\u5fc5\u987b\u58f0\u660e\u5728HAVING\u4e2d\u3002\r\n#      \u5f53\u8fc7\u6ee4\u6761\u4ef6\u4e2d\u6ca1\u6709\u805a\u5408\u51fd\u6570\u65f6\uff0c\u5219\u6b64\u8fc7\u6ee4\u6761\u4ef6\u58f0\u660e\u5728WHERE\u4e2d\u6216HAVING\u4e2d\u90fd\u53ef\u4ee5\u3002\u4f46\u662f\uff0c\u5efa\u8bae\u5927\u5bb6\u58f0\u660e\u5728WHERE\u4e2d\r\n\r\n\/*\r\n WHERE \u4e0e HAVING \u7684\u5bf9\u6bd4\r\n 1. \u4ece\u9002\u7528\u8303\u56f4\u4e0a\u6765\u8bb2\uff0cHAVING\u7684\u9002\u7528\u8303\u56f4\u66f4\u5e7f\u3002\r\n 2. \u5982\u679c\u8fc7\u6ee4\u6761\u4ef6\u4e2d\u6ca1\u6709\u805a\u5408\u51fd\u6570\uff1a\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cWHERE\u7684\u6267\u884c\u6548\u7387\u8981\u9ad8\u4e8eHAVING\r\n\r\n *\/\r\n\r\n# 4. SQL\u5e95\u5c42\u6267\u884c\u539f\u7406\r\n# 4.1 SELECT \u8bed\u53e5\u7684\u5b8c\u6574\u7ed3\u6784\r\n\r\n\/*\r\n\r\n #SQL92\u8bed\u6cd5\uff1a\r\n SELECT ....,....,....(\u5b58\u5728\u805a\u5408\u51fd\u6570)\r\n FROM ....,....\r\n WHERE \u591a\u8868\u7684\u8fde\u63a5\u6761\u4ef6 AND \u4e0d\u5305\u542b\u805a\u5408\u51fd\u6570\u7684\u8fc7\u6ee4\u6761\u4ef6\r\n GROUP BY ....,....\r\n HAVING \u5305\u542b\u805a\u5408\u51fd\u6570\u7684\u8fc7\u6ee4\u6761\u4ef6\r\n ORDER BY ....,....(ASC \/ DESC)\r\n LIMIT ....,....\r\n\r\n  #SQL99\u8bed\u6cd5\uff1a\r\n SELECT ....,....,....(\u5b58\u5728\u805a\u5408\u51fd\u6570)\r\n FROM ....(LEFT \/ RIGHT)JOIN....ON \u591a\u8868\u7684\u8fde\u63a5\u6761\u4ef6\r\n (LEFT \/ RIGHT)JOIN .... ON ....\r\n WHERE \u4e0d\u5305\u542b\u805a\u5408\u51fd\u6570\u7684\u8fc7\u6ee4\u6761\u4ef6\r\n GROUP BY ....,....\r\n HAVING \u5305\u542b\u805a\u5408\u51fd\u6570\u7684\u8fc7\u6ee4\u6761\u4ef6\r\n ORDER BY ....,....(ASC \/ DESC)\r\n LIMIT ....,....\r\n\r\n *\/\r\n\r\n# 4.2 SQL\u8bed\u53e5\u7684\u6267\u884c\u8fc7\u7a0b\uff1a\r\n# FROM ....,.... -> ON -> (LEFT\/RIGHT JOIN) -> WHERE -> GROUP BY -> HAVING -> SELECT -> DISTINCT ->\r\n# ORDER BY -> LIMIT<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[47],"class_list":["post-1522","post","type-post","status-publish","format-standard","hentry","category-mysql-code","tag-mysql"],"_links":{"self":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1522"}],"collection":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1522"}],"version-history":[{"count":1,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1522\/revisions"}],"predecessor-version":[{"id":1523,"href":"https:\/\/qaqaq.top\/index.php?rest_route=\/wp\/v2\/posts\/1522\/revisions\/1523"}],"wp:attachment":[{"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1522"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1522"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/qaqaq.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1522"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}