Parameter to filter in the where clause SSRS

Question

I have an SSRS report that filters the Items based on whether its an Type I (Item) or A (Accessories). Currently this is multi select parameter where I have specified the values. But I would like to change this to a single select-able value with the following values:

• All- Items and Accessories
• I - Items
• A - Accessories
• E - Items exclude Category A and Products D

Is it possible to have case condition statements within the where clause like the following:

WHERE 
(CASE WHEN @Pram1 IN ('A') THEN ('I,'A')
      WHEN @Pram1 IN ('I') THEN ('I')
      WHEN @Pram1 IN ('E') THEN ('I')
 ELSE 
 -1 END)

THEN based on this I will have the conditions for the Categories. IF its 'A' then it will include all categories. IF 'E' then all from the category parameter which is also a multi select but not include Category A.

Answer 1

You cannot just have a case statement by itself as listed in OP. You can however apply a SQL filter conditionally by using a pattern such as this:

SELECT * 
FROM yourProductsTable p
WHERE 
--Apply the "type" filters
(
    (
        @TypeParam = 'All' --then include both Items and Accessories
        AND p.ProductType in ('I','A')
    )
    OR 
    (
        @TypeParam = 'A' --Accessories only
        AND p.ProductType = 'A'
    )
    OR
    (
        @TypeParam = 'I' --Items only
        AND p.ProductType = 'I'
    )
    OR
    (
        @TypeParam = 'E' --Items only, but Exclude Category A and Product D
        AND p.ProductType = 'I'
        AND p.Category <> 'A'
        AND p.Product <> 'D'
    )
)
--Apply Other filters: i.e. category
AND p.Category in (@SSRSCategoryMultiSelectParam)