Question

我已经创建了2个case语句来从单个表中提取数据（它被创建为2个单独的case语句，因为我想要重复计算值，并且作为单个case语句，它没有这样做）。

2个案例陈述产生了2个新的数据列（案例陈述A和案例陈述B）。但是，我希望在一个列中报告2个case语句值，所以我试图找到一种方法将这两个列组合在一起。

这是我的查询。我对SQL很新（只用了一个星期！）所以请原谅我查询中的任何愚蠢的语法。

select b.part_month, count(a.pay_code), sum(a.amount),
CASE
when a.pay_code like 'CC%' THEN 'Credit Card Payment'
when a.pay_code like 'DC%' then 'Debit Card Payment'
Else 'N/A'
End as Payment_Type,

CASE
when a.pay_code like '%IP%' then 'Internet Payment'
when a.pay_code like '%TT%' then 'Touchtone Payment'
Else 'N/A'
End as Payment_Type

from table_a A
inner join table_b B on A.form_ID = B.ID
where a.trans_type > 0
and b.st_id = 2

group by B.PART_MONTH,
CASE
when a.pay_code like 'CC%' THEN 'Credit Card Payment'
when a.pay_code like 'DC%' then 'Debit Card Payment'
Else 'N/A'
End,

CASE
when a.pay_code like '%IP%' then 'Internet Payment'
when a.pay_code like '%TT%' then 'Touchtone Payment'
Else 'N/A'
End
order by b.part_month asc;

Answer 1

为您提供CASE个别名，然后将查询包装到GROUP BY个别名。

结合您的CASE语句，假设这是您想要的。

SELECT * FROM (
    SELECT b.part_month, 
    COUNT(a.pay_code) AS PayCodeCount,
    SUM(a.amount) AS AmountSum,
    CASE a.pay_code 
        WHEN 'CC%' THEN 'Credit Card Payment'
        WHEN 'DC%' THEN 'Debit Card Payment'
        WHEN '%IP%' THEN 'Internet Payment'
        WHEN '%TT%' THEN 'Touchtone Payment'
        ELSE 'N/A'
    END AS Payment_Type
    FROM table_a A
    INNER JOIN table_b B ON A.form_ID = B.ID
    WHERE a.trans_type > 0
    AND b.st_id = 2) Z
GROUP BY PART_MONTH, Payment_Type
ORDER BY part_month ASC;

Answer 2

我猜你想要：

select b.part_month, count(a.pay_code), sum(a.amount),
       (case when a.pay_code like 'CC%' then 'Credit Card Payment'
             when a.pay_code like 'DC%' then 'Debit Card Payment'
             when a.pay_code like '%IP%' then 'Internet Payment'
             when a.pay_code like '%TT%' then 'Touchtone Payment'
             else 'N/A'
        end) as Payment_Type
from table_a a inner join
     table_b b
     on a.form_ID = b.ID
where a.trans_type > 0 and b.st_id = 2
group by b.part_month,
         (case when a.pay_code like 'CC%' then 'Credit Card Payment'
               when a.pay_code like 'DC%' then 'Debit Card Payment'
               when a.pay_code like '%IP%' then 'Internet Payment'
               when a.pay_code like '%TT%' then 'Touchtone Payment'
               else 'N/A'
          end)
order by b.part_month asc;

重要的是：某些数据库允许您使用group by中的别名，接受group by b.part_month, payment_type。

Answer 3

感谢您的帮助。 Gordon Linoff，我已经尝试了你的查询，但是这让我得到了我最初开始的结果，然后将case语句拆分为2。

pay_code％IP％和％TT％也可以匹配CC％和DC％语句，如果匹配，则不计算IP或TT值。但是，我需要计算匹配％IP％，％TT％，CC％和DC％的所有值，即使这意味着重复计算某些数据行。

因此，pay_code列中的值可能是“DCIP”，“CCTT”，“CCIP”等。从这些值中，我想知道有1个DC付款，2个CC付款，2个IP付款和1个TT付款。

这就是我的表最终会看到单个case语句的方式。请注意，没有互联网付款或按键付款条目。

Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment
N/A
Credit Card Payment
Debit Card Payment

Answer 4

答案是

Select * from (select b.part_month, count(a.pay_code), sum(a.amount),
CASE
when a.pay_code like '%IP%' then 'Internet Payment'
when a.pay_code like '%TT%' then 'Touchtone Payment'
Else 'N/A'
End as Payment_Type

from table_a A
inner join table_b B on A.form_ID = B.ID
where a.trans_type > 0
and b.st_id = 2

group by B.PART_MONTH,
CASE
when a.pay_code like '%IP%' then 'Internet Payment'
when a.pay_code like '%TT%' then 'Touchtone Payment'
Else 'N/A'
End

Union

select b.part_month, count(a.pay_code), sum(a.amount),
CASE
when a.pay_code like 'CC%' THEN 'Credit Card Payment'
when a.pay_code like 'DC%' then 'Debit Card Payment'
Else 'N/A'
End as Payment_Type

from table_a A
inner join table_b B on A.form_ID = B.ID
where a.trans_type > 0
and b.st_id = 2

group by B.PART_MONTH,
CASE
when a.pay_code like 'CC%' THEN 'Credit Card Payment'
when a.pay_code like 'DC%' then 'Debit Card Payment'
Else 'N/A'
End)

Order by 1,4;

如何结合两个case语句列

4 个答案: