双表查询是把记录多的放前面还是把记录小的放前面
表users 字段 userid,departid,username 记录10000
表depart 字段 departid departname 记录1000000
双表查询
查询1,select * from users as a,depart as b where a.departid=b.departid
查询2,select * from depart as a,users as b where a.departid=b.departid
查询3 select * from users as a join depart as b on a.departid=b.departid
哪种快呢