Question

I have a stored procedure that is heavily using multiple level of nested dervied tables. I am just wondering what is the best method of debugging this type of queries where you can look into what is coming from the inner derived tables etc? Any thoughts?

Answer 1

Sometimes, I’ll at least temporarily pull those derived tables out into a table variable or temp table so I can get a better look at what’s going on.

So, in an over-simplified example:

select *
    from table_a
        inner join (select * from table_b) b
        ...

would become

select * 
    into #tempb
    from table_b

select * from #tempb /* for debugging purposes */

select *
    from table_a
        inner join #tempb b
        ...