将三 (3) 个查询合并为一个

Question

我想将这三个查询合并为一个查询：

SELECT County, Result1, COUNT(Result1) AS Result1Total
FROM MainData
WHERE (((Date) BETWEEN '01/01/2020' AND '01/30/2020'))
GROUP BY County, Result1
ORDER BY County;

SELECT County, Result2, COUNT(Result2) AS Result2Total
FROM MainData
WHERE (((Date) BETWEEN '01/01/2020' AND '01/30/2020'))
  AND Result2 <> 'NULL'
GROUP BY County, Result2
ORDER BY County;

SELECT County, Result3, COUNT(Result3) AS Result3Total
FROM MainData
WHERE (((Date) BETWEEN '01/01/2020' AND '01/30/2020'))
  AND Result3 <> 'NULL'
GROUP BY County, Result3
ORDER BY County;

我希望输出如下所示：

County        Result         Totals
-----------------------------------    
Allegany      Car Services     2
Richmond      Car Services     3
Lynchberg     House Services   5
Charlotte     Car Services     12
Charlotte     House Services   2
NorthHampton  Car Serivces     6
NorthHampton  House Services   8

结果1、2、3是下拉框，内容相同

Answer 1

如果列总计表示 resulttotal 的国家/地区明智结果之和，那么您的查询将是：

select Country, Result, sum(Result1Total) Totals
from (
    SELECT County, Result1 Result, Count(Result1) AS Result1Total
    FROM MainData
    WHERE (((Date) Between '01/01/2020' And '01/30/2020'))
    GROUP BY County, Result1


    union all

    SELECT County, Result2, Count(Result2) AS Result2Total
    FROM MainData
    WHERE (((Date) Between '01/01/2020' And '01/30/2020'))
    AND Result2 <> 'NULL'
    GROUP BY County, Result2

    union all

    SELECT County, Result3, Count(Result3) AS Result3Total
    FROM MainData
    WHERE (((Date) Between '01/01/2020' And '01/30/2020'))
    AND Result3 <> 'NULL'
    GROUP BY County, Result3
)
group by County, Result
ORDER BY County;

Answer 2

看起来 GROUPING SETS 在这里会派上用场：

SELECT
    County,
    ISNULL(ISNULL(Result1, Result2), Result3) AS Result,
    COUNT(Result1) AS Result1Total
FROM MainData
WHERE (((Date) BETWEEN '01/01/2020' AND '01/30/2020'))
GROUP BY GROUPING SETS (
    (County, Result1),
    (County, Result2),
    (County, Result3)
)
ORDER BY County;

如果 Result 列可以为空，那么您需要更复杂的表达式：

    CASE WHEN GROUPING(Result1) = 0 THEN Result1
         WHEN GROUPING(Result1) = 0 THEN Result2
         ELSE Result3
    END AS Result,

将三 (3) 个查询合并为一个

Combine three (3) queries into one

sql

tsql

sql-server

sql-server-2012

sql-server-2016