Sql 使用Pivot计算最近两天的数据更改百分比

我有一个表，其中包含每天收集的一组数据（我使用SQL Server 2016）

我正在尝试编写一个查询，该查询将显示最近两天和%的更改，并返回如下结果：

Field  Today   Yesterday  Change(%)
A       1.1       1.0       10.0%
B       2.1       2.0        5.0%
C       3.1       3.0        3.3%
D       4.1       4.0        2.5%

---

有没有一种快速的方法可以做到这一点（我假设pivot涉及某个地方，但我真的无法解决此查询）

这应该可以满足您的需要：

select
    FieldValue                          as  [Field]
    , case FieldValue 
        when 'A'
            then ta
        when 'B'
            then tb
        when 'C'
            then tc
        when 'D'
            then td
        end                             as  [Today]
    , case FieldValue 
        when 'A'
            then ya
        when 'B'
            then yb
        when 'C'
            then yc
        when 'D'
            then yd
        end                             as  [Yesterday]
    , Change                            as  [Change(%)]
    from
    (select
        t1.a                            as  [ta]    -- today's A value
        , t1.b                          as  [tb]    -- today's B value
        , t1.c                          as  [tc]    -- today's C value
        , t1.d                          as  [td]    -- today's D value
        --, t1.e                        as  [te]    -- today's E value
        -- make sure to include the t1.e, t1.f etc. for other Fields too

        , y.a                           as  [ya]    -- yesterday's A value
        , y.b                           as  [yb]    -- yesterday's B value
        , y.c                           as  [yc]    -- yesterday's C value
        , y.d                           as  [yd]    -- yesterday's D value
        --, y.e                         as  [ye]    -- yesterday's E value
        -- make sure to include the y.e, y.f etc. for other Fields too

        , 100 / (y.a / (t1.a - y.a))    as  [A]     -- A's change since yesterday
        , 100 / (y.b / (t1.b - y.b))    as  [B]     -- B's change since yesterday
        , 100 / (y.c / (t1.c - y.c))    as  [C]     -- C's change since yesterday
        , 100 / (y.d / (t1.d - y.d))    as  [D]     -- D's change since yesterday
        --, 100 / (y.e / t1.e - y.e))   as  [E]     -- E's change since yesterday (INCLUDE this "E" alias in the list of columns from UNPIVOT)
        -- make sure to add calculations for your other fields here too

    from baseTable t1
        cross apply (select top 1 * 
                     from baseTable t2 
                     where t2.date < t1.date) y
    where t1.date = (select max(date) from baseTable)
    ) result
unpivot (
    Change for FieldValue in (a, b, c, d) --, e, f etc.) -- enumerate all column ALIASES used in the sub-select, where the CHANGE is calculated
    ) as unpvt

---

这将为您提供您需要的：

select
    FieldValue                          as  [Field]
    , case FieldValue 
        when 'A'
            then ta
        when 'B'
            then tb
        when 'C'
            then tc
        when 'D'
            then td
        end                             as  [Today]
    , case FieldValue 
        when 'A'
            then ya
        when 'B'
            then yb
        when 'C'
            then yc
        when 'D'
            then yd
        end                             as  [Yesterday]
    , Change                            as  [Change(%)]
    from
    (select
        t1.a                            as  [ta]    -- today's A value
        , t1.b                          as  [tb]    -- today's B value
        , t1.c                          as  [tc]    -- today's C value
        , t1.d                          as  [td]    -- today's D value
        --, t1.e                        as  [te]    -- today's E value
        -- make sure to include the t1.e, t1.f etc. for other Fields too

        , y.a                           as  [ya]    -- yesterday's A value
        , y.b                           as  [yb]    -- yesterday's B value
        , y.c                           as  [yc]    -- yesterday's C value
        , y.d                           as  [yd]    -- yesterday's D value
        --, y.e                         as  [ye]    -- yesterday's E value
        -- make sure to include the y.e, y.f etc. for other Fields too

        , 100 / (y.a / (t1.a - y.a))    as  [A]     -- A's change since yesterday
        , 100 / (y.b / (t1.b - y.b))    as  [B]     -- B's change since yesterday
        , 100 / (y.c / (t1.c - y.c))    as  [C]     -- C's change since yesterday
        , 100 / (y.d / (t1.d - y.d))    as  [D]     -- D's change since yesterday
        --, 100 / (y.e / t1.e - y.e))   as  [E]     -- E's change since yesterday (INCLUDE this "E" alias in the list of columns from UNPIVOT)
        -- make sure to add calculations for your other fields here too

    from baseTable t1
        cross apply (select top 1 * 
                     from baseTable t2 
                     where t2.date < t1.date) y
    where t1.date = (select max(date) from baseTable)
    ) result
unpivot (
    Change for FieldValue in (a, b, c, d) --, e, f etc.) -- enumerate all column ALIASES used in the sub-select, where the CHANGE is calculated
    ) as unpvt

---

我会首先使用一个窗口功能，比如

行数

来获取前两个日期，然后将

a

、

B

、

C

和

d

的列取消分割成行，从而得到结果。一旦你完成了这项工作，你就可以将这些结果转化为最终想要的产品

对此进行分解，我将首先使用

行编号

：

select [Date], A, B, C, D,
  rn = row_number() over(order by [Date] desc) 
from #yourtable

这将为表中的每一行创建一个唯一的行id，您可以按日期对其排序，以生成所需顺序的日期。接下来，您将把

A

、

B

、

C

、和

D

列解压成行：

select 
  Field,
  value, 
  Dt = case when rn = 1 then 'Today' else 'Yesterday' end
from
(
  select [Date], A, B, C, D,
    rn = row_number() over(order by [Date] desc) 
  from #yourtable
) x
cross apply
(
  values
  ('A', A),
  ('B', B),
  ('C', C),
  ('D', D)  -- include additional columns here if you have more
) c (Field, value)
where rn <= 2 -- return top 2 dates

这是一本书。这将为您提供以下结果：

Field Today Yesterday ChangePercent 
----- ----- --------- ------------- 
A     1.1   1         10            
B     2.1   2         5             
C     3.1   3         3.33          
D     4.1   4         2.5           

---

我会首先使用一个窗口功能，比如

行数

来获取前两个日期，然后将

a

、

B

、

C

和

d

的列取消分割成行，从而得到结果。一旦你完成了这项工作，你就可以将这些结果转化为最终想要的产品

对此进行分解，我将首先使用

行编号

：

select [Date], A, B, C, D,
  rn = row_number() over(order by [Date] desc) 
from #yourtable

这将为表中的每一行创建一个唯一的行id，您可以按日期对其排序，以生成所需顺序的日期。接下来，您将把

A

、

B

、

C

、和

D

列解压成行：

select 
  Field,
  value, 
  Dt = case when rn = 1 then 'Today' else 'Yesterday' end
from
(
  select [Date], A, B, C, D,
    rn = row_number() over(order by [Date] desc) 
  from #yourtable
) x
cross apply
(
  values
  ('A', A),
  ('B', B),
  ('C', C),
  ('D', D)  -- include additional columns here if you have more
) c (Field, value)
where rn <= 2 -- return top 2 dates

这是一本书。这将为您提供以下结果：

Field Today Yesterday ChangePercent 
----- ----- --------- ------------- 
A     1.1   1         10            
B     2.1   2         5             
C     3.1   3         3.33          
D     4.1   4         2.5           

---

字段的数量有限吗？是的。在现实世界的例子中，我有14个字段，您希望

max（date）

作为基础，并在此基础上计算

今天

和

昨天

？是的。这是正确的，字段的数量是有限的吗？是的。在现实世界的例子中，我有14个字段，您希望

max（date）

作为基础，并在此基础上计算

今天

和

昨天

？是的。没错，谢谢你。这很有效，你解释得很好。谢谢你。这很有效，你解释得很好。谢谢你的回答。我选择了下面一个更简洁的问题，但我感谢你的努力。谢谢你的回答。我选择了下面一个更简洁的查询，但我感谢您所做的努力。