select 材质规格,sum(数量) as 数量
from (select * from 材料仓库 union all select * from 施工单) a
group by 材质规格

------解决方案--------------------
SQL code

select * from 材料仓库 unoin all select * from 施工单

select 材料规格,sum(用料) 用料 from 
  (select * from 材料仓库 unoin all select * from 施工单) a
group by 材料规格

------解决方案--------------------
SQL code
select * from 材料仓库 unoin all select * from 施工单

select 材质规格,sum(数量) 数量 from 
  (select * from 材料仓库 unoin all select * from 施工单) a
group by 材质规格

------解决方案--------------------
SQL code

select 材质规格,sum(用料) 用料 from 
  (select 材质规格,用料 from 材料仓库 unoin all select 材质规格,用料 from 施工单) a
group by 材质规格

------解决方案--------------------
select 材质规格,sum(数量) as 数量
from (select * from 材料仓库 union all select * from 施工单) a
group by 材质规格

------解决方案--------------------
SQL code
select 材质规格,sum(数量) 总数量 from ( 
select 材质规格 
      , 数量 as 用料 
  from 材料仓库 
union all 
select 材质规格 
      , 用料 
  from 施工 
) t group by 材质规格

------解决方案--------------------
select 材质规格,sum(数量) 总数量  
 from ( select 材质规格  , 数量 as 用料  
           from 材料仓库  
          union all  
        select 材质规格  , 用料  
           from 施工  
       ) t  
  group by 材质规格

------解决方案--------------------
探讨

SQL codeselect a.材料牌号,(a.数量 - (b.数量 * b.毛重)) as 库存量 
from 材料仓库 as a left join 
    施工单 as b on a.材料牌号 = b.材料牌号


------解决方案--------------------
mark
select 材料规格,sum(数量) from (select * from 材料仓库 union select * from 施工单) t group by t.name