A simple double-entry ledger with source and destination accounts in SQL

Hey everyone! I wrote a blog post about building a simple double-entry ledger using just simple SQL. It covers implementing a ledger with source and destination accounts, using a simple table structure and straight-forward SQL queries for balance calculations. I use negative and positive amounts instead of traditional debit and credit columns. In my opinion, this from/to model is easier to reason about and visualize in graph form, while still allowing credit/debit terminology to be built on top if needed. Would love to hear your thoughts!