I’ve built a query and done some calculations in new columns. Now, I only want to see a subset of that query in my final results. Is this where I would use a union? Apologies if this is not the correct place to ask beginner questions like this. Trying to learn for my new job.

Select BookValue, MarketValue, Allowance, MarketValue - (BookValue - Allowance) As Unrealized 
FROM Holdings.table

^ this is the query I currently built but now I just want to see in my final results the records with an allowance that have Unrealized greater than 0.

Any suggestions?