Php 一条sql语句比两条好?
因此,我有以下两条sql语句,我想将它们合并为一条Php 一条sql语句比两条好?,php,mysql,sql,Php,Mysql,Sql,因此,我有以下两条sql语句,我想将它们合并为一条 SELECT `client_id` FROM `accommodation` WHERE `checkin` >= from AND `checkout` <= to SELECT `client_id` FROM `conference` WHERE `checkin` >= from AND `checkout` <= to 从“住宿”中选择“客户id”,其中“签入”>=FROM和“签出”=FROM和“签出”假设
SELECT `client_id` FROM `accommodation` WHERE `checkin` >= from AND `checkout` <= to
SELECT `client_id` FROM `conference` WHERE `checkin` >= from AND `checkout` <= to
从“住宿”中选择“客户id”,其中“签入”>=FROM和“签出”=FROM和“签出”假设“满足条件”,您的意思是两个条件都满足。这意味着一个连接
。所以试试这个:
SELECT a.`client_id`
FROM `accommodation` a join
conference c
on a.client_id = c.client_id
WHERE a.checkin >= from AND a.checkout <= to and
c.checkin >= from AND c.checkout <= to;
选择一个.`client\u id`
从`住宿'开始加入
会议c
在a.client\u id=c.client\u id上
其中a.checkin>=from和a.checkout=from和c.checkout可能使用联合