I have this stored Procedure that is passed in the data below that will building the SQL select that will get EXEC. The data that can be passed in can me null so I have three `IF ISNULL` checking and then adding to the `@SqlWhereCommand` object. Any help would be great.

parameter

    @StartDate AS DATE = NULL, 
    @EndDate AS DATE = NULL, 
    @Ids As Varchar(500) = NULL, 
    @SubCategories As Varchar(300) = NULL, 
    @LanguageIds As Varchar(300) = NULL, 
    @RegionIds As Varchar(300) = NULL, 

DECLARE 

    DECLARE @SqlCommand nvarchar(4000)  
    DECLARE @SQLColumnList varchar(2000) 
    DECLARE @SqlSelectCommand nvarchar(4000)  
    DECLARE @SqlFromCommand varchar(200)  
    DECLARE @SqlWhereCommand nvarchar(2000)  
    DECLARE @SqlGroupCommand nvarchar(4000) 

Buildings the Selects

    SET @SQLColumnList =' Id, [Name] as ''gl.Name'', type = ''PDF'', CONCAT([Description],''Data Stats'') as Description, 
    SUM (WebsiteDownloads) As Downloads,[Language],
    Region = ''Asia'''
    		
    Set @SqlFromCommand =' from [report].[Downloads]'
    Set @SqlGroupCommand =' GROUP BY Id, [Name],[Description],[Language]'
    Set @SqlWhereCommand = ' where cast(LogDate as date) >= + ''' + CONVERT(VARCHAR(25), @StartDate, 120) + ''' and cast(LogDate as date) <= ''' + CONVERT(VARCHAR(25), @EndDate, 120) + ''''		
    
    
    
    IF ((ISNULL(@Ids,'')) <> '')  
    	BEGIN 
    		SET @SqlWhereCommand = @SqlWhereCommand + ' AND Id IN (SELECT val AS linkType FROM dbo.Split(''' + @Ids + ''','',''))' 
    	END
    
    IF ((ISNULL(@SubCategories,'')) <> '')  
    	BEGIN 	
    		SET @SqlWhereCommand = @SqlWhereCommand + ' AND LinkTypeId IN (SELECT val As subCategorys FROM dbo.Split(''' + @SubCategories + ''', '',''))' 
    	END 
    
    IF ((ISNULL(@LanguageIds,'')) <> '')  
    	BEGIN 
    	SET @SqlWhereCommand = @SqlWhereCommand + ' AND LanguageId IN (SELECT val As subCategorys FROM dbo.Split(''' + @LanguageIds + ''', '',''))' 
    END 
    
    SET @SqlCommand = 'SELECT ' + @SQLColumnList + @SqlFromCommand + @SqlWhereCommand + @SqlGroupCommand