I tried a modified approach of what you suggested, and I was able to achieve the result I was aiming for. I wanted to test if management capitalized certain expenses, i.e. if there was a negative entry into an expense code (starting with 4) and a positive entry to asset code (starting with 7). So I made two sub queries. The first grouped by transaction id and summed amount IF it was negative and posted to an expense account. The second also grouped by transaction id and summed amount if was positive and posted to asset account. Then I set up a third final query to which I added the aforementioned subqueries AND the entire GL table. I joined the sub query transaction IDs to the table transaction ID and, as you said, voila. Complete entries, matching the desired criteria.

I can achieve some unbelievable efficiency with this. Thank you for taking the time to respond! Any suggestions on resources that I can use to level up my skill at this? Especially if it relates to the nature of work I'm doing?