比较三列中的空值，并将最新数据放入/写入非空的列。 [英] Compare null value in three columns and put/ write the latest data into the column which is not null.

问题描述

  SELECT  R. [FORM_ID]，R.APPROVAL_STATUS，A.FORM_ID，A.APPROVAL_DECISION，S.FORM_ID，S。 APPROVAL_DECISION，
 ISNULL（S.APPROVAL_DECISION，A.APPROVAL_DECISION） AS  AD3 
  FROM  [PREV_REQUEST_TO_RECRUIT]  AS  R 
  LEFT  加入 [HR_AUTHORISATION]  ON  R.FORM_ID = A.FORM_ID 
  left  < span class =code-keyword> join  [SEN_MGR_AUTHORISATION] S   R.FORM_ID = S.FORM_ID 

当你们两个S都可以帮助我将R.APPROVAL_STATUS的值输入到同一列AD3中.APPROVAL_DECISION，A.APPROVAL_DECISION为空。





谢谢，

Sathish

解决方案

COALESCE应该在这种情况下帮助你。它返回第一个非空值。

  SELECT   COALESCE （S.APPROVAL_DECISION，A.APPROVAL_DECISION，R.APPROVAL_STATUS） AS  SomeColumn 

或者，如果由于某种原因你不想要前2个值而你的条件只是在前2个为空时获得第三个你可以使用CASE声明。

  SELECT   CASE   WHEN  S.APPROVAL_DECISION  IS   NULL   AND  A.APPROVAL_DECISION  IS   NULL  那么 R.APPROVAL_STATUS  ELSE  '  WhateverYouWant'  END   AS  SomeColumn 

SELECT R.[FORM_ID], R.APPROVAL_STATUS,A.FORM_ID,A.APPROVAL_DECISION, S.FORM_ID,S.APPROVAL_DECISION,
ISNULL(S.APPROVAL_DECISION,A.APPROVAL_DECISION)  AS AD3
FROM [PREV_REQUEST_TO_RECRUIT] AS R
LEFT JOIN [HR_AUTHORISATION] A  ON  R.FORM_ID=A.FORM_ID
left join [SEN_MGR_AUTHORISATION] S on R.FORM_ID = S.FORM_ID

Could you please help me in getting the value of R.APPROVAL_STATUS into the same column AD3 when both S.APPROVAL_DECISION,A.APPROVAL_DECISION is null.


Thanks,
Sathish

解决方案

COALESCE should help you in this case. It returns the first non-null value.

SELECT COALESCE(S.APPROVAL_DECISION,A.APPROVAL_DECISION, R.APPROVAL_STATUS) AS SomeColumn

Or, if for some reason you don't want the first 2 values and your condition is to get the third only when the first 2 are null you can use a CASE statement.

SELECT CASE WHEN S.APPROVAL_DECISION IS NULL AND A.APPROVAL_DECISION IS NULL THEN R.APPROVAL_STATUS ELSE 'WhateverYouWant' END AS SomeColumn

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