要从表AA中查询所有字段,条件是AA.id等于表BB的id,
表BB.id 查询条件是 BB.name='zhang' BB.sex='nv' 也就是说当BB.name='zhang' BB.sex='nv' 时得到BB.id,由BB.id去AA中查AA.id=BB.id的所有字段。
表BB.id 查询条件是 BB.name='zhang' BB.sex='nv' 也就是说当BB.name='zhang' BB.sex='nv' 时得到BB.id,由BB.id去AA中查AA.id=BB.id的所有字段。
Select AA.* From AA, BB
Where AA.id = BB.id And BB.name='zhang' And BB.sex='nv'
Select AA.* From AA Inner Join BB
On AA.id = BB.id
Where BB.name='zhang' And BB.sex='nv'
Where a.id = a.id And b.name='zhang' And b.sex='nv'select * from aa
where id in (select id from bb
where name='zhang' and sex='nv')