如何执行复杂的sql语句并在数组中获取结果？(How to execute a complex sql statement and get the results in an array?)

 我想使用SQLite.swift执行一个相当复杂的SQL语句，并将结果最好放在一个数组中，以用作tableview的数据源。 声明如下： 
 
SELECT defindex, AVG(price) FROM prices WHERE quality = 5 AND price_index != 0 GROUP BY defindex ORDER BY AVG(price) DESC
 
 我正在研究SQLite.swift文档，以了解如何正确地完成它，但我找不到办法。 我可以在数据库上调用prepare并遍历Statement对象，但这不是最佳的性能。 
 
 任何帮助，将不胜感激。 

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.

原文：https://stackoverflow.com/questions/29986270