SQLServer的一个进销存问题

Question

数据库问题。一个购进数量表，一个销售数量表。如何即时动态得到库存数字。sql语句该怎么写？谢谢

select a.shl-b.shl as 库存数量 from
(SELECT SUM(shl),spid from ywsys_ywmx where djbh like 'JHD%' and zzrq>='2015-01-01' group by spid) a
(select SUM(shl),spid from ls_daymxls where rq>='2015-01-01' group by spid)b where a.spid=b.spid
报错 不知道怎么回事

Answer 1

报什么错？上表结构和测试数据。

(SELECT SUM(shl),spid from ywsys_ywmx where djbh like 'JHD%' and zzrq>='2015-01-01' group by spid) a ,
(select SUM(shl),spid from ls_daymxls where rq>='2015-01-01' group by spid)b where a.spid=b.spid

少个逗号。