如题：要求FactoryNo、List_id相等，表#A有输入SizeID的，按相同的SizeID取汇总，没有的按FactoryNo、List_id相等取汇总。
if object_id('tempdb.dbo.#A') is not null drop table #A
create table #A(FactoryNo varchar(10),List_id varchar(10), SizeID varchar(10),Quantity int)
insert into #A
select '8','111','',1 union all
select '8','111','',2 union all
select '8','111','',3 union all
select '8','111','',4 union all
select '8','112','S',2 union all
select '8','112','M',3 union all
select '8','112','',4 union all
select '8','112','XL',5
if object_id('tempdb.dbo.#A') is not null drop table #B
create table #B(FactoryNo varchar(10),List_id varchar(10), SizeID varchar(10),Quantity int)
insert into #B
select '8','111','S',2 union all
select '8','111','M',3 union all
select '8','111','L',4 union all
select '8','111','XL',5 union all
select '8','112','S',6 union all
select '8','112','M',7 union all
select '8','112','L',8 union all
select '8','112','XL',9
结果显示如下：
FactoryNo List_id SizeID Quantity TotQty
---------- ---------- ---------- ----------- -----------
8 111 1 14
8 111 2 14
8 111 3 14
8 111 4 14
8 112 S 2 6
8 112 M 3 7
8 112 4 30
8 112 XL 5 9
select 关联表 部分相等