sql - INNER Join 的案例声明

Question

尝试在内部联接上使用 CASE 语句，但我得到的只是语法错误，有人对此有任何建议吗？

这是代码

 SELECT  
    Call_type_ID,
    SUM (staging.dbo.outgoing_measure.ring_time) AS Ring_Time,
    SUM (staging.dbo.outgoing_measure.hold_time) As Hold_Time,
    SUM (staging.dbo.outgoing_measure.talk_time) AS Talk_Time,
    SUM (staging.dbo.outgoing_measure.acw_time) AS ACW_Time,
    COUNT(*) CallCount
FROM outgoing_measure

INNER JOIN datamartend.dbo.Call_Type_Dim ON 
CASE 
WHEN 
CTICallType_ID = 1
AND CTIAgentCallType_ID = 0
AND Abandoned  IS NULL
AND AnsTime > 0
AND CallState IS NULL
THEN Call_Type_ID = 10
WHEN
CTICallType_ID = 1
AND CTIAgentCallType_ID = 0
AND Abandoned  IS NULL
AND AnsTime > 0  
AND CallState = 1
THEN call_Type_id = 11
WHEN 
CTICallType_ID = 1
AND CTIAgentCallType_ID = 0
AND Abandoned = 1
AND AnsTime IS NULL
AND CallState IS NULL
THEN call_type_ID = 12
ELSE call_type_id = 1
END

Group by call_Type_id

这是我第一次使用 case 语句，更不用说将它们与内部联接相结合，所以如果我完全搞砸了，我很抱歉。

我遇到的语法错误是:

此处 = 和 WHEN 的语法不正确

THEN Call_Type_ID = 10
WHEN

语法错误，需要在 GROUP BY 上进行 CONVERSION

Answer 1

您似乎正在尝试在案例中创建Where子句，但您应该将案例的结果与Call_Type_ID(或您想要的任何其他字段)进行比较，如我在下面编写的示例中所示希望对您有帮助!

有时我会在外壳上使用括号，以便更容易看到它们的开始和停止位置。

INNER JOIN datamartend.dbo.Call_Type_Dim ON 
(CASE 
 WHEN  CTICallType_ID = 1
     AND CTIAgentCallType_ID = 0
     AND Abandoned  IS NULL
     AND AnsTime > 0
     AND CallState IS NULL
     THEN 10
WHEN CTICallType_ID = 1
     AND CTIAgentCallType_ID = 0
     AND Abandoned  IS NULL
     AND AnsTime > 0  
     AND CallState = 1
     THEN 11
WHEN 
     CTICallType_ID = 1
     AND CTIAgentCallType_ID = 0
     AND Abandoned = 1
     AND AnsTime IS NULL
     AND CallState IS NULL
     THEN 12
ELSE 1
END) = Call_Type_ID  -- Insert something here to join on.