Boolean Logic in Select Statement

Question

How do I implement boolean logic in the select statement while the query is running?

SELECT t.[Key]
      ,t.[Parent_Key]
      ,t.[Parent_Code]
      ,t.[Code]
      ,t.[Desc] 
      ,t.[Point]
      ,[isChild] -- If Point > 2, then true, if Point == 1 Then false   
      ,t.[By] 
      ,t.[On]
FROM [db].[stats] t WHERE t.[Parent_Key]= @tmpParameter

I want make some logic to determine [isChild] boolean value based on t.[Point]

[CASE](http://msdn.microsoft.com/en-us/library/ms181765.aspx) — Habib, Jul 11 '14 at 14:39

score 5 · Accepted Answer · answered Jul 11 '14 at 14:44

SELECT t.[Key]
      ,t.[Parent_Key]
      ,t.[Parent_Code]
      ,t.[Code]
      ,t.[Desc] 
      ,t.[Point]
      ,CASE WHEN t.[Point] > 2 THEN 1 ELSE  
            CASE WHEN t.[Point] = 1 THEN 0 ELSE NULL END 
       END AS [isChild]
      ,t.[By] 
      ,t.[On]
FROM [db].[stats] t WHERE t.[Parent_Key]= @tmpParameter

Be aware that when t.[Point] < 1 then [isChild] will be null

score 1 · Answer 2 · answered Jul 11 '14 at 14:42

1

Case is your friend...

 SELECT Key, Parent_Key, Parent_Code, Code, Desc, point, 
     case when point > 2 then 1 
          when point = 1 then 0 end isChild, 
     [By], [On]
 FROM db.stats  
 WHERE Parent_Key= @tmpParameter

answered Jul 11 '14 at 14:42

Charles Bretana

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score 0 · Answer 3 · answered Jul 11 '14 at 14:40

Use the case statement:

SELECT t.[Key]
      ,t.[Parent_Key]
      ,t.[Parent_Code]
      ,t.[Code]
      ,t.[Desc] 
      ,t.[Point]
      ,CASE t.[Point] WHEN 1 THEN FALSE WHEN 2 THEN TRUE END as [isChild]
      ,t.[By] 
      ,t.[On]
FROM [db].[stats] t WHERE t.[Parent_Key]= @tmpParameter

score 0 · Answer 4 · answered Jul 11 '14 at 14:41

You can use CASE statement

SELECT t.[Key]
  ,t.[Parent_Key]
  ,t.[Parent_Code]
  ,t.[Code]
  ,t.[Desc] 
  ,t.[Point]
  ,CASE 
  WHEN t.[Point] THEN true 
  else false
  END as isChild
  ,t.[By] 
  ,t.[On]
FROM [db].[stats] t WHERE t.[Parent_Key]= @tmpParameter

Boolean Logic in Select Statement

4 Answers4