【Oracle&SQLServer】并集、交际、补集

1、并集（UNION/UNION ALL）

Oracle&SQLServer中用法一致

UNION	去重
UNION ALL	不去重

-- 去重
select * from tablea
union
select * from tableb

-- 不去重
select * from tablea
union all
select * from tableb

 2、交集（INTERSECT/EXISTS）

Oracle&SQLServer中用法一致

INTERSECT	去重
EXISTS	不去重

-- 去重
select * from tablea
intersect
select * from tableb

-- 不去重
select * from tablea a
where exists (select 1 from tableb b where a.ID=b.ID)

3、补集（MINUS/EXCEPT/NOT EXISTS）

Oracle：

MINUS	去重
NOT EXISTS	不去重

SQLServer：

EXCEPT	去重
NOT EXISTS	不去重

-- Oracle去重
select * from tablea
minus
select * from tableb

-- SQLServer去重
select * from tablea
except
select * from tableb

-- Oracle&SQLServer不去重
select * from tablea a
where not exists (select 1 from tableb b where a.ID=b.ID)