select * from A,B,C where A.pk_sign=B.pk_sign and A.pk_fmcrit=C.pk_fmcrit
select * from A,B where A.pk_sign=B.pk_sign union all select * from A,C where A.pk_fmcrit=C.pk_fmcritselect m.* , n.* from (select * from A,B where A.pk_sign=B.pk_sign) m, (select * from A,C where A.pk_fmcrit=C.pk_fmcrit) n where m.某字段 = n.某字段select * from a , b, c where A.pk_sign=B.pk_sign and A.pk_fmcrit=C.pk_fmcrit
select * from (select * from A,B where A.pk_sign=B.pk_sign) a, (select * from A,C where A.pk_fmcrit=C.pk_fmcrit) b where a.关联字段 = b.关联字段
where A.pk_sign=B.pk_sign and A.pk_fmcrit=C.pk_fmcrit
union all
select * from A,C where A.pk_fmcrit=C.pk_fmcritselect m.* , n.* from
(select * from A,B where A.pk_sign=B.pk_sign) m,
(select * from A,C where A.pk_fmcrit=C.pk_fmcrit) n
where m.某字段 = n.某字段select * from a , b, c where A.pk_sign=B.pk_sign and A.pk_fmcrit=C.pk_fmcrit
*
from
(select * from A,B where A.pk_sign=B.pk_sign) a,
(select * from A,C where A.pk_fmcrit=C.pk_fmcrit) b
where
a.关联字段 = b.关联字段