两个表的合并问题

[hellohz]

我现在有两个结构完全一样的表A和B

我现在想把B中的所有记录全部追加到A的后面，请问应该是怎样的SQL语句？

[pengdali]

insert B select * from a

[Rewiah]

如果有重复
insert B select * from a
where not exists (select 1 from b where keyfield=a.keyfield)

[HawaiiLeo]

insert A select * from B

[HawaiiLeo]

insert A select * from B
where not exists (select * from A where keyfield = B.keyfield)