mysql中为同一张表取多个别名&为某一列取别名

select employee1.name as employee from employee
              employee1,employee employee2 where employee1.managerId=employee2.id and
              employee1.salary>employee2.salary;

这里给同一张表取别名的方法是，

select 列名 as 新列名 from 表名 新表名1，表名 新表名2；

 

如果name重复出现，想要在多个name中只保留一个，则在表名前面加distinct；

select distinct employee1.salary as employee from employeer
              employee1,employeer employee2 where employee1.id!=employee2.id and
              employee1.salary=employee2.salary ;