How to execute a complex sql statement and get the results in an array?

I would like to execute a fairly complex SQL statement using SQLite.swift and get the result preferably in an array to use as a data source for a tableview. The statement looks like this:

SELECT defindex, AVG(price) FROM prices WHERE quality = 5 AND price_index != 0 GROUP BY defindex ORDER BY AVG(price) DESC

I was studying the SQLite.swift documentation to ind out how to do it properly, but I couldn't find a way. I could call prepare on the database and iterate through the Statement object, but that wouldn't be optimal performance wise.

Any help would be appreciated.