sql 语句中 in 和 =的区别
select * from students where studentname='张三'select * from students where studentname in('张三','李四','王五')--或select * from students where studentname in(select studentname from signinfo)
你应该明白区别了吧
请教高手在sql里in,all,any,some的区别和具体应用范围
停课不停学 some 和any的特殊用法