如何从中创建视图 select，并将其与现有 table

Question

所以这是生成我想要的数据的代码 table 1.

with data as 
(
    select
        CP_REF,
        count(*) * 1.0 /
          nullif(count(case when QUANTITY > 0 then 1 end), 0) as ADI,
          stdevp(QUANTITY) / nullif(avg(QUANTITY), 0) as COV
    from 
        DF_ALL_DEMAND_BY_ROW_V
    where 
        parent is not null
    group by 
        CP_REF
)
select
    CP_REF, ADI, COV
    case
        when ADI <  1.32 and COV * COV <  0.49 then 'Smooth'
        when ADI >= 1.32 and COV * COV <  0.49 then 'Intermittent'
        when ADI <  1.32 and COV * COV >= 0.49 then 'Erratic'
        when ADI >= 1.32 and COV * COV <= 0.49 then 'Lumpy'
        else 'No Quantity Measured'
    end
from data;

这提供了一个非常优雅的解决方案...

这就是我要找的，但是，现在我需要获取此数据并将其与原始 table DF_ALL_DEMAND_BY_ROW_V 合并。我希望它包含 DF_ALL_DEMAND_BY_ROW_V 中存在的所有内容，但将上面的数据加入 CP_REF，我认为这是一个 LEFT JOIN，但我无法弄清楚。

Answer 1

不确定这是否是您的意思，但是为什么不创建第二个 CTE 并加入其中，例如

with data as (
    select
    ...
), Q2 as (
  select
    CP_REF, ADI,
    case
        when ADI <  1.32 and COV * COV <  0.49 then 'Smooth'
        when ADI >= 1.32 and COV * COV <  0.49 then 'Intermittent'
        when ADI <  1.32 and COV * COV >= 0.49 then 'Erratic'
        when ADI >= 1.32 and COV * COV <= 0.49 then 'Lumpy'
        else 'Smooth'
    end as StatusOrWhatever
  from data
)
select stuff
from DF_ALL_DEMAND_BY_ROW_V v
left join Q2 on D2.CF_REF = v.CP_REF

如何从中创建视图 select，并将其与现有 table

How do I create a view, select from it, and join it with an existing table

sql

sql-server

join