SQL Server2000中Group By的用法？

select fname,lname,hire_date,job_lvl
from(select * from employee
where(hire_date between '1990-1-1' and '1990-12-31')
union all
select * from employee
where job_lvl>100) a--这里加个表别名看看
group by hire_date,job_lvl,fname,lname
having (count(*)>1)

select fname,lname,hire_date,job_lvl
from(
select fname,lname,hire_date,job_lvl from employee where(hire_date between '1990-1-1' and '1990-12-31')
union all
select fname,lname,hire_date,job_lvl from employee where job_lvl>100
) temptable
group by hire_date,job_lvl,fname,lname
having (count(*)>1)

select 表名.列名
from 表名
where 条件
group by 要分组的表的列名

其实group by 在SQL是用来分组的。