[英]mysql:best way to optimize this sql query
我想以最好的方式從此查詢中獲取結果
這是我的桌子指示
學校
CREATE TABLE `schools` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user` mediumint(5) NOT NULL,
`gender` tinyint(1) NOT NULL,
`time` int(11) NOT NULL,
`status` tinyint(2) NOT NULL,
`number` mediumint(6) NOT NULL,
`name` varchar(75) NOT NULL,
`address` varchar(75) NOT NULL,
`admin` varchar(50) NOT NULL,
`admin_phone` varchar(20) NOT NULL,
`admin_email` varchar(30) NOT NULL,
`school_phone` varchar(20) NOT NULL,
`learn` tinyint(2) NOT NULL,
`mr7la` tinyint(2) NOT NULL,
`sfof` smallint(3) NOT NULL,
`fswl` smallint(3) NOT NULL,
`json` text NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `user` (`user`),
KEY `status` (`status`),
KEY `learn` (`learn`),
KEY `mr7la` (`mr7la`),
KEY `number` (`number`)
) ENGINE=MyISAM AUTO_INCREMENT=20 DEFAULT CHARSET=utf8
3agz
CREATE TABLE `3agz` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`school` int(11) NOT NULL,
`tkss` int(11) NOT NULL,
`teacher_7ess` int(11) NOT NULL,
`teacher_master_7ess` int(11) NOT NULL,
`time_added` int(11) NOT NULL,
`reported` int(11) NOT NULL DEFAULT '0',
`fixed` int(11) NOT NULL,
`info` text NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `school` (`school`,`tkss`,`teacher_7ess`,`fixed`),
KEY `school_2` (`school`),
KEY `tkss` (`tkss`),
KEY `reported` (`reported`),
KEY `time_added` (`time_added`),
KEY `school_3` (`school`,`time_added`),
KEY `school_4` (`school`,`fixed`)
) ENGINE=InnoDB AUTO_INCREMENT=85 DEFAULT CHARSET=utf8
這是為此的SQL小提琴
http://sqlfiddle.com/#!2/3313e0/4
你可以看到她是我使用的SQL查詢
SELECT
schools.* , ( select count(id) from 3agz where 3agz.school = schools.id and fixed = 0 ) as has_3agz
FROM
schools
WHERE
( select count(id) from 3agz where 3agz.school = schools.id and fixed = 0 ) > 0
limit 10
的解釋是
學校=>小學:全部
3agz => DEPENDENT子查詢:ref
3agz => DEPENDENT子查詢:ref
這是我問我可以這樣做嗎,什么是最好的方法
1-我可以忽略第二個子查詢的位置並取決於選擇中的第一個子查詢嗎
2-如果數字1的答案是您不能執行此查詢后,我不能忽略第一個子查詢[has_3agz別名],我循環拋出結果[schools ids]
然后像這樣進行第二次查詢
例如,第一個查詢返回的學校ID為1、2、3、4
select school , count(id) from 3agz where school in ( 1 , 2 , 3 , 4 ) and fixed = 0
將每個計數附加到數組中的學校
希望你能理解我
最好的祝福
SELECT schools.*, count(*) as has_3agz from schools
LEFT JOIN 3agz on 3agz.school = schools.id and fixed = 0
GROUP BY schools.id;
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