create table A (ID int, 名称 varchar(20))
insert A select 1 ,'CPU'
union all select 2 ,'MEMORY'
union all select 3 ,'LCD'
union all select 4 ,'MOUSE'
create table B (ID int, B数量 int, 单位  varchar(20))
insert b select 1 ,12 ,'公斤'
union all select 1 ,5 ,'箱'
union all select 2, 10 ,'公斤'
union all select 2 ,15 ,'公斤'
create table C (ID int, C数量 int,单位  varchar(20))
insert c select 1 ,5 ,'公斤'
union all select 3, 10 ,'公斤'
create table D ( ID int, D数量 int, 单位  varchar(20))
insert d select 1 ,10 ,'箱'
union all select 2 ,10 ,'箱'
union all select 3 ,5, '箱'
SELECT  A.[名称]
,MAX(CASE B.BillType WHEN 1 THEN B.数量 ELSE 0 END) AS [B数量]
,MAX(CASE B.BillType WHEN 2 THEN B.数量 ELSE 0 END) AS [C数量]
,MAX(CASE B.BillType WHEN 3 THEN B.数量 ELSE 0 END) AS [D数量]
,B.[单位]
FROM A AS A INNER  JOIN
(SELECT [id],sum(B数量) AS [数量],[单位],1 AS BillType FROM B GROUP BY [id],[单位]
UNION ALL SELECT [id],sum(C数量),[单位],2  FROM C GROUP BY [id],[单位]
UNION ALL SELECT [id],sum(D数量),[单位],3  FROM D GROUP BY [id],[单位]
) AS B ON A.[id]=B.[id]
GROUP BY A.[id],A.[名称],B.[单位]
drop table A
drop table B
drop table C
drop table D