import SQLite3 

//connect to database file "data.sqlite"
let dbPath = Bundle.main.path(
    forResource: "data", ofType: "sqlite")!
var db: OpaquePointer? = nil
sqlite3_open(dbPath, &db)

let sql = """
    SELECT
        Language, Percentage
    FROM countrylanguage
    WHERE CountryCode = 'RUS'
    ORDER BY Percentage DESC
"""

var pointer: OpaquePointer?
sqlite3_prepare_v2(db, sql, -1, &pointer, nil)

while sqlite3_step(pointer) == SQLITE_ROW {
    let text = sqlite3_column_text(pointer, 0)
    let lang = String(cString: text!)
    let percent = sqlite3_column_double(pointer, 1)
    print("\(lang): \(percent)")
}

sqlite3_finalize(pointer)