How to improve query performance that inserts data into multiple tables that combines it

Question

So in my first table I am retrieving only ID's. Then creating and populating multiple table variable and filtering it by :

where exists(select * from @ID d where d.ID = @TableData.ID) 

so structure looks like this:

    --------------------------------------------
    declare @DateFrom datetime
            @DateTo datetime 
        --table that contain IDs only
              declare @ID table (ID int) 
              insert into @ID 
                select ID 
                from Table
                where dates between @DateFrom and @DateTo 

        --table with data
        declare @TableData
              select 
                case...
                case...
                case...
                case...
            from Table1
                    join Table1
                    join Table1
                    join Table1
            where exists(select * from @ID d where d.ID = @TableData.ID) --filtering only match IDs from @ID table

------------------------------------------------------------------

Is any way to improve performance somehow?

I tried to create #TempTable instead but still, no improvements.

I thought maybe there is a way to create index on table variables or temp tables?

Answer 1

You can create table variables with a primary key but you cannot use non-clustered indexes.

If you need to use indexes on temporary tables you should use #tempTables instead. You can then create indexes on those. When working with large data sets the # performs better than the @.