當月和上月數據

Question

下表具有數據類型如下：

ITEMNAME VARCHAR，日期日期，金額爲varchar，狀態VARCHAR

ItemName  Date  Amt  

    ABC  1/02/2012  500  
    ABC  8/03/2012  250  

預期結果

ItemName LastMonthAmt CurrentMonthAmt 

ABC   500    250 

請幫我寫下這個問題的查詢。

在此先感謝。

我曾嘗試如下：

declare @T table 
(
    id varchar(2), 
    [Date] datetime, 
    [Amt] varchar(5), 
    [Status] varchar(5) 
) 

insert into @T 
select '01', '1/02/12', '125', 'LM' union all 
--select '01', '1/02/12', '200', 'Exit' union all 
select '01', '2/02/12', '250', 'CM' union all 
--select '01', '2/02/12', '150', 'CM' union all 
select '02', '1/02/12', '300', 'LM' union all 
--select '02', '1/02/12', '350', 'CM' union all 
--select '02', '2/02/12', '220', 'LM' union all 
select '02', '2/02/12', '140', 'CM' 

select id, 
     --convert(varchar(8), [Date], 1) as [Date], 
     [Amt] as [CM], 
     [Amt] as [LM] 
from 
    (
    select distinct id, 
      [Amt], 
      row_number() over(partition by id order by [Date] asc) as rn1, 
      row_number() over(partition by id order by [Date] desc) as rn2 
    from @T 
) as T 
where T.rn1 = 1 or 
     T.rn2 = 1 
group by id, [Amt] 

Answer 1

可以使用聚合函數類似下面的CASE表達：

select itemname, 
    sum(case when month(date) = month(getdate()) -1 then amt else 0 end) LastMonthAmt, 
    sum(case when month(date) = month(getdate()) then amt else 0 end) CurrentMonthAmt 
from yourtable 
group by itemname; 

見SQL Fiddle with Demo