Question

我想将WHERE子句应用于我的select查询的一个字段。互联网告诉我在我选择我的字段然后删除where子句的行中使用CASE WHEN。但后来我被告知我的＆＃34; selected non aggregate values must be part of the associated group."

原始查询如下所示：

SELECT 
    CAST(EVENT_TIMESTAMP AS DATE) AS Date1, 
    COUNT(DISTINCT EMAIL) END AS Subs, 
    SUM(DWELL_MINUTES) AS Dwell
FROM VwNIMEventFct
INNER JOIN VwNIMUserDim ON VwNIMUserDim.NIM_USER_ID = VwNIMEventFct.NIM_USER_ID
INNER JOIN TmpNIMSalesForceDB ON VwNIMUserDim.USER_EMAIL_ADDRESS = EMAIL


WHERE Date1 >= '2013-11-01'
// The problem is here, in the AND clause
AND (SUBSCRIPTION_END_DATE > VwNIMEventFct.EVENT_TIMESTAMP OR SUBSCRIPTION_END_DATE 
IS NULL)

GROUP BY Date1
ORDER BY Date1

然后我在做了一些搜索之后更改了查询：

  SELECT 
    CAST(EVENT_TIMESTAMP AS DATE) AS Date1, 
    CASE WHEN (SUBSCRIPTION_END_DATE > Date1 OR SUBSCRIPTION_END_DATE IS NULL)
        THEN COUNT(DISTINCT TmpNIMSalesForceDB.EMAIL) END AS Subs, 
    SUM(VwNIMEventFct.DWELL_MINUTES) AS Dwell
    FROM RDMAVWSANDBOX.VwNIMEventFct
   INNER JOIN VwNIMUserDim ON VwNIMUserDim.NIM_USER_ID = VwNIMEventFct.NIM_USER_ID
   INNER JOIN TmpNIMSalesForceDB ON VwNIMUserDim.USER_EMAIL_ADDRESS = EMAIL
   WHERE Date1 >= '2013-11-01'
   GROUP BY Date1
   ORDER BY Date1

我想选择： 1）日期为＆＃34;日期1＆＃34;在查询中，然后， 2）对于每个日期，SUBSCRIPTION_END_DATE为NULL或将来（大于Date1）的不同电子邮件地址的计数， 3）一个字段的总和（我在这里很好）

我如何做2号？

根据答案编辑：这部分select查询是否忽略，因此不计算空白记录 SUBSCRIPTION_END_DATE为空？

SELECT 
    COUNT(DISTINCT CASE  WHEN TmpNIMSalesForceDB.SUBSCRIPTION_END_DATE > Date1 OR TmpNIMSalesForceDB.SUBSCRIPTION_END_DATE IS NULL
             THEN TmpNIMSalesForceDB.EMAIL END) AS Subs,

我需要计算SUBSCRIPTION_END_DATE为空/空的所有记录，或者那些日期在Date1之后的记录。

Answer 1

您需要将CASE语句放在COUNT中，而不是反之亦然，因为需要针对每一行（这行应该属于哪一行）进行评估，然后在每个组中进行聚合（该组中有多少行）落在非空组中。）

 COUNT(DISTINCT CASE WHEN (SUBSCRIPTION_END_DATE > Date1 OR SUBSCRIPTION_END_DATE IS NULL)
    THEN TmpNIMSalesForceDB.EMAIL END) AS Subs

COUNT将忽略CASE语句中缺少ELSE子句而隐式留下的NULL，因此只计算满足条件的行中不同的EMAIL值。

Answer 2

将case语句放在count函数内。

SELECT 
    CAST(EVENT_TIMESTAMP AS DATE) AS Date1, 
    COUNT(DISTINCT(CASE 
             WHEN SUBSCRIPTION_END_DATE > Date1 OR SUBSCRIPTION_END_DATE IS NULL
             THEN TmpNIMSalesForceDB.EMAIL END)) AS Subs, 
    SUM(VwNIMEventFct.DWELL_MINUTES) AS Dwell
FROM RDMAVWSANDBOX.VwNIMEventFct
    INNER JOIN VwNIMUserDim 
        ON VwNIMUserDim.NIM_USER_ID = VwNIMEventFct.NIM_USER_ID
    INNER JOIN TmpNIMSalesForceDB 
        ON VwNIMUserDim.USER_EMAIL_ADDRESS = EMAIL
WHERE Date1 >= '2013-11-01'
GROUP BY Date1
ORDER BY Date1

SQl将where子句应用于仅一个字段

2 个答案: