1.
select ...from... [into...] //distinct去重 ； top n 项数
where... //
group by... //分组
having... //指定组或聚合的搜索条件
order by... //排序
compute... //附加函数
union [all] express2//
2.
with 临时命名 的结果集
eg:
with ageReps(age,ageCount) as
(
select age,count(*) from employee
group by age
)
select age,ageCount from ageReps