Question

I have a query which looks like this:

SELECT  LossCost, CoverageID                
FROM BGILossCost] 
WHERE CoverageID IN (1, 2) AND
      StateID = @StateID AND
      ConstructionID = @ConstructionID AND
      PropertyClassCodeID = @PropertyClassCodeID AND
      (BGIDistrictID = @BGIDistrictID OR BGIDistrictID IS NULL)           

And returns the following data, which is correct:

LossCost                                CoverageID
--------------------------------------- -----------
0.012                                   1
0.034                                   2

But what I want to do is set two variables depending in the value of CoverageID

Here is the pseudeo code:

SELECT  @Var1 = CASE CoverageID = 1 THEN LossCost END,
  @Var2 = CASE CoverageID = 2 THEN LossCost END             
FROM BGILossCost] 
WHERE CoverageID IN (1, 2) AND
      StateID = @StateID AND
      ConstructionID = @ConstructionID AND
      PropertyClassCodeID = @PropertyClassCodeID AND
      (BGIDistrictID = @BGIDistrictID OR BGIDistrictID IS NULL) 

I could always do the below but I was hoping I wouldn’t have to join to the same table twice for performance reasons

SELECT  @Var1 = LossCost                    
FROM BGILossCost] 
WHERE CoverageID = 1 AND
      StateID = @StateID AND
      ConstructionID = @ConstructionID AND
      PropertyClassCodeID = @PropertyClassCodeID AND
      (BGIDistrictID = @BGIDistrictID OR BGIDistrictID IS NULL) 

SELECT  @Var2 = LossCost                    
FROM BGILossCost] 
WHERE CoverageID = 2 AND
      StateID = @StateID AND
      ConstructionID = @ConstructionID AND
      PropertyClassCodeID = @PropertyClassCodeID AND
      (BGIDistrictID = @BGIDistrictID OR BGIDistrictID IS NULL) 

Any suggestions would be helpful.

Answer 1

You were very close, doesn’t this work:

SELECT
  @Var1 = MAX(CASE WHEN CoverageID = 1 THEN LossCost END),
  @Var2 = MAX(CASE WHEN CoverageID = 2 THEN LossCost END)  
FROM BGILossCost
WHERE CoverageID IN (1, 2) AND
      StateID = @StateID AND
      ConstructionID = @ConstructionID AND
      PropertyClassCodeID = @PropertyClassCodeID AND
      (BGIDistrictID = @BGIDistrictID OR BGIDistrictID IS NULL);