How to solve a problem with SQLite in Swift?

Question

SQLite

Good afternoon. Can you please tell me how in the stephencelis/SQLite.swift library ( https://github.com/stephencelis/SQLite.swift ) it is possible to implement a calculated column from other columns in the select? Which can then be used when displaying data, as well as in order by? I tried several options, but always writes that this column was not found (because it was not saved in the database)
An example of what needs to be solved:
SELECT a+b as c from test ORDER BY c ASC;

I also encountered a problem in the like method in conjunction with LOWER (for comparison, case-insensitive), the problem is in comparing Russian characters, they are not converted to lowercase... Perhaps someone solved this problem?
Example:

// in name value: ПРИВЕТ from database
let search_name = "Привет"
user.filter(name.lowercaseString.like("%" + search_name.lowercased() + "%"))

Thanks a lot for your help.