select partno,入库量,kcsl 库存数 from (select partno,sum(rksl) 入库量 from rkdmx where rkddate between '开始日期' and '结束日期' group by partno) a Inner Join kc b on a.partno=b.partno
select A.partno, A.partname ,B.入库量, A.kcsl from kc A left outer join (select partno,sum(rksl) 入库量 from rkdmx where rkddate between '开始日期' and '结束日期' group by partno) B on A.partno = B.partno
left outer join
(select partno,sum(rksl) 入库量 from rkdmx where rkddate between '开始日期' and '结束日期' group by partno) B
on A.partno = B.partno