Adding index in table suggestion? I have a table called Products with ID(PK, Clustered), Name, Price, Brand, ...., RetailerID, SKU, ModelNumber. My query have 

SELECT .... 
FROM Products 
WHERE RetailerID = @RetailerID AND 
      ( (@SKU != '' AND SKU = @SKU)  OR (@ModelNumber != '' AND ModelNumber = @ModelNumber))


I am going to add index for this query. Should I add 3 indices on RetailerID , SKU and ModelNumber or 2 compound indices on (RetailerID, SKU) and (RetailerID, ModelNumber) or 1 compund index on (RetailerID, ModelNumber, SKU)
I'd create a seperate index on SKU and ModelNumber. I don't think an index on RetailerID will do much good as there won't be many different retailers . 

The best approach to analyze this is by comparing the execution plans &amp; times of the different sets of indexes