Question

我有一个简单的表，其中只包含几千条记录，其中性能不是主要考虑因素。

我想计算列表中1和5年间隔的同一列中值之间的差异。

例如，我们说我有一张这样的表：

Name, Year, Value<br>

Joe       2014       25<br>
Joe       2013       22<br>
Joe       2012       26<br>
Joe       2011       18<br>
Joe       2010       21<br>
Mark      2014       33<br>
Mark      2013       31<br>
Mark      2012       34<br>
Mark      2011       28<br>
Mark      2010       18<br>

它可以追溯到几年前。

我想为1 year change和5 year change添加两列关于给定名称的运行差异。

所以完成的输出看起来像这样（如果可能的话）：

Name, Year, Value, 1-yr-change, 5-yr-change<br>
Joe       2014       25           3               4<br>
Joe       2013       22           -4              <whatever 2013-2009 is><br>
Joe       2012       26           8           <br>    
Joe       2011       18           -3<br>
Joe       2010       21           <whatever 2010-2009 is><br>
Mark      2014       33           2               15<br>
Mark      2013       31           -3              <whatever 2013-2009 is><br>
Mark      2012       34           6<br>
Mark      2011       28           10<br>
Mark      2010       18           <whatever 2010-2009 is><br>

这是我尝试使用表格中的实际列的原因：

select t1.Agency, t1.FY, t1.[Tax Appropriations],<br>
case when t2.FY = T1.FY - 1 then T1.[Tax Appropriations] - T2.[Tax Appropriations] else null end as '1-yr-change',<br>
case when t2.FY = T1.FY - 5 then T1.[Tax Appropriations] - T2.[Tax Appropriations] else null end as '5-yr-change'<br>
from dbo.SHEFMain as t1<br>
left JOIN dbo.SHEFMain as t2 on T1.Agency = T2.Agency and T2.FY < T1.FY<br>
order by agency, fy desc<br>

结果有效，但是还有很多额外的重复行也带有空值 - 所以我显然误解了连接过程或类似的东西。

Answer 1

我在另一个论坛上得到了答案 - 感谢您的帮助！这就是我得到的东西，似乎完美无缺。如果您有任何意见或疑虑，请与我们联系：

select t1.Agency
     , t1.FY
     , t1.[Tax Appropriations]
     , t1.[Tax Appropriations] - (SELECT T2.[Tax Appropriations] 
                             FROM dbo.SHEFMain as t2 
                             WHERE T2.Agency = T1.Agency 
                             AND T2.FY = T1.FY-1) as '1-yr-change'
     , t1.[Tax Appropriations] - (SELECT T3.[Tax Appropriations] 
                             FROM dbo.SHEFMain as t3 
                             WHERE t3.Agency = T1.Agency 
                             AND T3.FY = T1.FY-5) as '5-yr-change'
from dbo.SHEFMain as t1
order by T1.agency, 
         T1.fy DESC

计算值列中1到5年间隔的差异

1 个答案: