SQLite.swift peforming a left join and using the data

I am trying to perform a left join

SELECT TProgram.ProgramName, TProgram.ProgramPath From TProgram
LEFT JOIN TIcons ON TIcons.ProgramName = TProgram.ProgramName
WHERE TIcons.ProgramName IS NULL
GROUP BY TProgram.ProgramName

with swift. So i did the following.

let program = db["TProgram"]
let icons = db["TIcons"]
let programNameDB = Expression<String>("ProgramName")
let programNameDBI = Expression<String>("ProgramName")
let programPathDB = Expression<String>("ProgramPath")
let all = program.select(programNameDB, programPathDB).join(Query.JoinType.LeftOuter, icons, on: programNameDB == icons[programNameDBI]).filter(programNameDBI != "").group(programNameDB)

i cannot check if it is working because the following results in an fatal error: ambiguous column name:

let item = all.first!
let arr = Array(all)

If I try println(all) I can see "TProgram" in the debug console.

How can i access the data?

UPDATE I tried the following. Error is gone but no values seem to be in there.

func readTProgramNames() -> (Query){
    let program = db["TProgram"]
    let icons = db["TIcons"]
    let programNameDB = Expression<String>("ProgramName")
    let programNameDBI = Expression<String>("ProgramName")
    let programPathDB = Expression<String>("ProgramPath")
    let all = program
        .select(program[programNameDB], program[programPathDB])
        .join(.LeftOuter, icons, on: program[programNameDB] == icons[programNameDBI])
        .filter(icons[programNameDBI] != "")
        .group(program[programNameDB])

    let item = all.first!

    println(item[program[programNameDB]])

    return all
}