Question

I have one master table with all the IDs to each child table. The SQL statement looks like this…

SELECT   Class.Descript
       , Regulation.Descript AS Reg
       , Compgroup.Descript AS Grouping
       , Category.Descript AS Cat
       , Exempt.Descript AS Exempt
       , Reason.Descript AS Reasons
       , COALESCE(ComponentRuleSet.NormalType, ComponentRuleSet.Supertype, '') AS Type
FROM     ComponentRuleSet 
LEFT OUTER JOIN Reason 
   ON ComponentRuleSet.ComponentCategoryID = Reason.ComponentCategoryID 
LEFT OUTER JOIN Class 
   ON ComponentRuleSet.ComponentClassID = Class.ComponentClassID
LEFT OUTER JOIN Regulation
   ON ComponentRuleSet.RegulationID = Regulation.RegulationID 
LEFT OUTER JOIN Compgroup
   ON ComponentRuleSet.ComplianceGroupID = Compgroup.ComplianceGroupID
LEFT OUTER JOIN Category 
   ON ComponentRuleSet.ComponentCategoryID = Category.ComponentCategoryId
LEFT OUTER JOIN Exempt 
   ON ComponentRuleSet.ExemptID = Exempt.ComponentExemptionID
WHERE (ComponentRuleSet.ComponentID = 38048)

The problem is that there are two fields in the ComponentRuleSet table called NormalType and Supertype. If either of those fields have a value, I need to display it in a column called Type. Yet, if neither have a value I need to display a Blank value in the Type column.
Any ideas?

—EDIT

Is my placement of COALESCE correct in the edited query? It is still returning errors.

–UPDATE

IMPORTANT: The type of both fields are boolean, I need to return the column name of the column that holds a TRUE value, and place that value in the TYPE column.

Answer 1

Seeing your comments, perhaps a CASE expression will work:

select ...
      , CASE WHEN ComponentRuleSet.NormalType is not null then 'NormalType'
             WHEN ComponentRuleSet.Supertype  is not null then 'SuperType'
             ELSE ''
             end as Type

UPDATE Since boolean values are just 1 for true and 0 for false, try this:

select ...
      , CASE WHEN ComponentRuleSet.NormalType = 1 then 'NormalType'
             WHEN ComponentRuleSet.Supertype  = 1 then 'SuperType'
             ELSE ''
             end as Type