可以试试这条语句:
select a.物品代码 as dm,sum(b.入库数量) as rksl from a,b
where a.物品代码 = b.物品代码
group by a.物品代码;
对于形成的两个字段dm,rksl就是dbgrid中可以显示的字段
select a.物品代码 as dm,sum(b.入库数量) as rksl from a,b
where a.物品代码 = b.物品代码
group by a.物品代码;
对于形成的两个字段dm,rksl就是dbgrid中可以显示的字段
SELECT 物品代码,数量=(SELECT SUM(B.入库数量 FROM B WHERE 物品代码 = P.物品代码) FROM A AS P