use Tempdb
go
--> --> 
 
if not object_id(N'Tempdb..#T1') is null
    drop table #T1
Go
Create table #T1([订单编号] nvarchar(21),[款号] int,[颜色] nvarchar(2),[尺码] nvarchar(2),[数量] decimal(18,8))
Insert #T1
select N'JHDD-2011-12-02-00002',699,N'米色',N'L',1.00000000 union all
select N'JHDD-2011-12-02-00002',699,N'米色',N'M',2.00000000 union all
select N'JHDD-2011-12-02-00002',699,N'米色',N'XL',15.00000000
Go

 
if not object_id(N'Tempdb..#T2') is null
    drop table #T2
Go
Create table #T2([款号] int,[颜色] nvarchar(2),[尺码] nvarchar(3))
Insert #T2
select 699,N'米色',N'L' union all
select 699,N'米色',N'M' union all
select 699,N'米色',N'XL' union all
select 699,N'米色',N'XXL'
Go
SELECT 
    a.*,
    b.[数量]
FROM (Select b.*,a.* from #T2 AS a,(SELECT DISTINCT [订单编号] FROM #T1) b) AS a
LEFT JOIN #T1 AS b ON a.[订单编号]=b.[订单编号] AND a.[款号]=b.[款号] AND a.[颜色]=b.[颜色] AND a.[尺码]=b.[尺码]

/*
订单编号    款号    颜色    尺码    数量
JHDD-2011-12-02-00002    699    米色    L    1.00000000
JHDD-2011-12-02-00002    699    米色    M    2.00000000
JHDD-2011-12-02-00002    699    米色    XL    15.00000000
JHDD-2011-12-02-00002    699    米色    XXL    NULL
*/