将多个 SQL select 语句组合为列

Question

将多个 select 语句组合为一列，不会给出所需的 output。 我在这里缺少什么？ Group by 子句未按预期工作。 我还需要对外部 Select 使用 GroupBy 吗？

SQL 查询：

use [Test_DB]
SELECT  a.fldYear,a.fldMonth, a.ConnPoints,b.NonConnPoints from 
(Select  DATEPART(YEAR, e.TestDate) as [fldYear], DATENAME(month,e.TestDate) as [fldMonth], count(e.equipid) as [ConnPoints] from dbo.equip e 
where e.pID<>0 and e.TestDate between '01-01-2020' and '12-31-2020' 
Group By  DATEPART(year,e.TestDate), DATENAME(month,e.TestDate), DATEPART(month,e.TestDate)) as a,

(Select  DATEPART(YEAR, e.TestDate) as [fldYear], DATENAME(month,e.TestDate) as [fldMonth], count(e.equipid) as [NonConnPoints] from dbo.equip e 
where e.PID=0 and e.TestDate between '01-01-2020' and '12-31-2020' 
Group By  DATEPART(year,e.TestDate), DATENAME(month,e.TestDate), DATEPART(month,e.TestDate)) as b

当前 Output：显示 2020 年的 144 行数据

fldYear  fldMonth     ConnPoints      NonConnPoints
    2020     January    13456             73456
    2020     February   8345666           8375666
    2020     January    13456             8366
    2020     April      734569            334469
    2020     February   8345666           13456
    2020     June       33456             3456
    2020     April      734569            45663

Output 我正在寻找：应该显示 2020 年 12 个月的数据

fldYear  fldMonth   ConnPoints      NonConnPoints
2020     January    13456             73456
2020     February   8345666           8375666
2020     March      734566            8366
2020     April      734569            334469
2020     May        43456             13456
2020     June       33456             3456
2020     July       5345663           45663
2020     August     345661            75661
2020     September  345662            245662
2020     November   345668            645668
2020     December   534566            538866

Answer 1

你只想要条件聚合：

select year(e.TestDate), month(e.TestDate),
       sum(case when e.pID <> 0 then 1 else 0 end) as ConnPoints,
       sum(case when e.pID = 0 then 1 else 0 end) as NonConnPoints
from dbo.equip e 
where e.TestDate between '2020-01-01' and '2020-12-31'
group by year(e.TestDate), month(e.TestDate)
order by year(e.TestDate), month(e.TestDate)