SQL集合运算:差集、交集、并集1、差集( except ) select a from t_a
except
select a from t_b
-- 也可写作:
select a from t_a where a not in (select a from t_b)海洋石油117
-- 多个字段时:
如将不尽 与古为新
select a,b from t_a
石婴
except
select a,b from t_b
锎252
select a,b from t_a where (a,b) not in (select a,b from t_b)
2、交集( intersect )
select a from t_a
intersect
select a from t_b
-- 也可写作:
select a from t_a where a in (select a from t_b)
poco图客
3、并集( union )
select a from t_a
cppuunion distinct
select a from t_b