Return multiple values and read data from multiple text boxes - flask with python

I work with flask as web server and with Python and sqlite3.
I would like to enable queries on SQLite db, and present the results. The problem is , flask only enables to return one value to present, but there is a case where the result contains more than one line. In addition, I am interested in finding results which depend on multiple conditions, so I need flask to get requests from multiple text boxes.
I have been struggling with the official guide for hours, but I have no idea how to make it works. Any help will be welcomed.