在 GROUP BY 子句中使用 EXISTS

Question

是否可以执行以下操作：
我有一个看起来像这样的表：

declare @tran_TABLE TABLE(
EOMONTH DATE,
AccountNumber INT,
CLASSIFICATION_NAME VARCHAR(50),
Value Float

)

INSERT INTO @tran_TABLE VALUES('2018-11-30','123','cat1',10)
INSERT INTO @tran_TABLE VALUES('2018-11-30','123','cat1',15)
INSERT INTO @tran_TABLE VALUES('2018-11-30','123','cat1',5 )
INSERT INTO @tran_TABLE VALUES('2018-11-30','123','cat2',10)
INSERT INTO @tran_TABLE VALUES('2018-11-30','123','cat3',12)
INSERT INTO @tran_TABLE VALUES('2019-01-31','123','cat1',5 )
INSERT INTO @tran_TABLE VALUES('2019-01-31','123','cat2',10)
INSERT INTO @tran_TABLE VALUES('2019-01-31','123','cat2',15)
INSERT INTO @tran_TABLE VALUES('2019-01-31','123','cat3',5 )
INSERT INTO @tran_TABLE VALUES('2019-01-31','123','cat3',2 )
INSERT INTO @tran_TABLE VALUES('2019-03-31','123','cat1',15)


EOMONTH     AccountNumber   CLASSIFICATION_NAME     Value
2018-11-30  123                     cat1                10
2018-11-30  123                     cat1                15
2018-11-30  123                     cat1                5
2018-11-30  123                     cat2                10
2018-11-30  123                     cat3                12
2019-01-31  123                     cat1                5
2019-01-31  123                     cat2                10
2019-01-31  123                     cat2                15
2019-01-31  123                     cat3                5
2019-01-31  123                     cat3                2
2019-03-31  123                     cat1                15

我想生成一个结果，它将检查每个月的每个 AccountNumber（在这种情况下只有一个）是否存在 CLASSIFICATION_NAME cat1、cat2、cat3。
如果该月所有 3 个都存在，则返回 1，但如果缺少任何一个，则返回 0。

结果应该是这样的：

EOMONTH     AccountNumber   CLASSIFICATION_NAME
2018-11-30    123                   1                               
2019-01-31    123                   1                       
2019-03-31    123                   0   

但我希望尽可能紧凑地进行操作，而不是先创建一个按 CLASSIFICATION_NAME、EOMONTH 和 AccountNumber 对所有内容进行分组的表，然后从该表中进行选择。
例如，在下面的伪代码中，是否可以使用 EXISTS 语句进行分组？

SELECT 
    EOMONTH
    ,AccountNumber
    ,CASE WHEN EXISTS (CLASSIFICATION_NAME = 'cat1' AND 'cat2' AND 'cat3') THEN 1 ELSE 0 end 
    ,SUM(Value) AS totalSpend
FROM @tran_TABLE
GROUP BY 
    EOMONTH
    ,AccountNumber

Answer 1

这样查询。您可以计算不同的值。 当您计算唯一值时，列“Three_Unique_Cat”。当您准确计算“cat1”、“cat2”、“cat3”时，列“Three_Cat1_Cat2_Cat3”

SELECT 
    EOMONTH, AccountNumber
    ,CASE WHEN
       COUNT(DISTINCT CLASSIFICATION_NAME)=3 THEN 1 
       ELSE 0 
    END AS 'Three_Unique_Cat'
    ,CASE WHEN 
       COUNT(DISTINCT CASE WHEN CLASSIFICATION_NAME IN ('cat1','cat2','cat3') 
        THEN CLASSIFICATION_NAME ELSE NULL END)=3 THEN 1 
       ELSE 0 
     END AS 'Three_Cat1_Cat2_Cat3'
    ,SUM(Value) AS totalSpend
FROM @tran_TABLE
GROUP BY EOMONTH, AccountNumber 

Output:
EOMONTH   AccountNumber Three_Unique_Cat    Three_Cat1_Cat2_Cat3    totalSpend
2018-11-30  123 1   1   52
2019-01-31  123 1   1   37
2019-03-31  123 0   0   15

Answer 2

很简单，如下：

select
    EOMONTH,
    AccountNumber,
    case when count(distinct CLASSIFICATION_NAME) = 3 then 1 else 0 end as CLASSIFICATION_NAME
from
    tran_TABLE
group by
    EOMONTH,
    AccountNumber

Answer 3

您可以通过计算满足此条件的不同分类（每组）来模拟此行为：

SELECT 
    EOMONTH
    ,AccountNumber
    ,CASE COUNT(DISTINCT CASE WHEN classification_name IN ('cat1', 'cat2', 'cat3') THEN classification_name END) 
          WHEN 3 THEN 1 
          ELSE 0 
     END
    ,SUM(Value) AS totalSpend
FROM @tran_TABLE
GROUP BY 
    EOMONTH
    ,AccountNumber

Answer 4

试试这个-

SELECT EOMONTH, 
AccountNumber,
CASE 
    WHEN COUNT(DISTINCT CLASSIFICATION_NAME) = 3 THEN 1
    ELSE 0
END CLASSIFICATION_NAME
FROM @tran_TABLE
GROUP BY EOMONTH,AccountNumber

输出是-

2018-11-30  123 1
2019-01-31  123 1
2019-03-31  123 0