数据透视表和列之间的百分比比较

Question

我是新手使用带有sql的数据透视表，并且一直坚持这个特殊问题，我希望有人可以提供帮助。我的脚本返回一个作业列表，并计算每年的作业。我想添加一个与上一年相比增加或减少百分比的列。

SELECT *
FROM
(
SELECT [year_time], [assignment_code], [assignment_desc]
FROM raw_teacher
) AS source
PIVOT
(
    COUNT(assignment_code)
    FOR [year_time] IN ([2012], [2011], [2010], [2009], [2008])
) as pvt

当前输出：

期望的输出......

Answer 1

您可以直接进行计算：

with cte as (
     SELECT *
     FROM
     (
     SELECT [year_time], [assignment_code], [assignment_desc]
     FROM raw_teacher
     ) AS source
     PIVOT
     (
         COUNT(assignment_code)
         FOR [year_time] IN ([2012], [2011], [2010], [2009], [2008])
     ) as pvt
    )
select assignment_desc, [2012], [2012]/[2011], [2011], [2011]/[2010],
                        [2010], [2010]/[2009], [2009], [2009]/[2008], [2008]
from cte

如果值可以为0，那么您需要检查：

select asignment_desc,
       [2012], (case when [2011] <> 0 then [2012]/[2011] end),
       [2011], (case when [2010] <> 0 then [2011]/[2010] end),
       . . .
from cte