sql多表查询

常用的多表联合查询的sql语句：
select spkfjc.*,spkfk.* from spkfjc inner join spkfk on spkfjc.spid=spkfk.spid
 where  spkfjc.spid='SPH00000078'

改进后：
select a.ID from table1 a,
(select col1,ID from table2 where col2='xxx') b
 where a.ID=b.ID