fnIsProjectComponentLinked

CREATE FUNCTION [dbo].[fnIsProjectComponentLinked](
@EmailProjectID int,
@AppealID int,
@AppealListID int,
@AppealListEmailID int
)
RETURNS BIT 

as
BEGIN

DECLARE @IsLinked bit

SET @IsLinked = 0

    IF EXISTS(SELECT NULL FROM Email e 
            INNER JOIN EmailProjectAppeal_ListEmail epale ON e.ProjectAppealListEmailID = epale.[ID]
            INNER JOIN EmailProjectAppeal_EmailList epael ON epale.EmailProjectAppealListID = epael.[ID]
            INNER JOIN EmailProjectAppeal epa ON epael.[EmailProjectAppealID] = epa.[ID]
            WHERE (epa.[EmailProjectID] = @EmailProjectID OR @EmailProjectID = 0) AND
            (epa.[ID] = @AppealID OR @AppealID = 0) AND (epael.[ID] = @AppealListID OR
            @AppealListID = 0) AND (epale.[ID] = @AppealListEmailID OR @AppealListEmailID = 0) and epale.[Deleted] = 0)
        SET @IsLinked = 1

RETURN @IsLinked


END