Is there an app that allows you to query the QBO database with SQL?

Hello Patrick-unthank 👋 Welcome to the Community. We can't advise on third-party apps as such but you are more than welcome to check the app store within QuickBooks and search for apps, For instance, I have searched SQL and have found 3 results but whether the apps showing is what you need you will need to look into them to ensure they have the features you require. We are more than happy for other customers who used something similar to comment. Thanks, Becky 

check out the vidi corp plugin, it extracts the data from QBO to an Azure SQL Server database. The plugin extracts the data in a very convenient format and has tables like P&L, Balance Sheet, etc. There is a frere trial as well so might be good to explore.