MySQL变量很多,其中有一些MySQL变量非常值得我们注意,下面就为您介绍一些值得我们重点学习的MySQL变量,供您参考。1 Threads_connected 首先需要注意的,想得到这个变量的值不能show variables like 'Threads_connected';而是show status like 'Th..
过程1:带返回值: drop procedure if exists proc_addNum; create procedure proc_addNum (in x int,in y int,out sum int) BEGIN SET sum= x + y; end然后,执行过程,out输出返回值: call proc_addNum(2,3,@sum);select @sum;过程2:不带返回值..
今天游戏和服,发现数据备份好后,导入不到目标库中,mysql -h10.66.125.733 --port 3306 -u sanda -pX12234455 --default-character-set=utf8 sanda_s10 < /data/mysql/8/user.sql返回ERROR 1044 (42000) at line 20: Access denied for user 'san..
在网上查找删除重复数据保留id最小的数据,方法如下:DELETEFROMpeopleWHEREpeopleName IN (SELECTpeopleNameFROMpeopleGROUP BYpeopleNameHAVINGcount(peopleName) > 1)AND peopleId NOT IN (SELECTmin(peopleId)FROMpeopleGROUP BYpeopleNameHAVI..