sql中到底 in 和 exist哪一个快?
第一个sql:
Delete From Log_Cust_Info WHERE EXISTS ( Select cust_id From CustomerWhere Customer.cust_id = Log_Cust_Info.cust_id AND Customer.CANCEL_DT < DATEADD(dd,-180,getdate())
第二个sql:
Delete From Log_Cust_Info WHERE cust_id in(Select cust_id from Customer Where CANCEL_DT < DATEADD(dd,-180,getdate())
上面这个sql是否相等的?执行速度哪个一个更快?