How to Concatenate a Select with the query()?

I'm use the query function, and what I want is to combine columns A, B, and C into a string with hyphens separating them. i.e. "2-4-6".

A|B|C
-|-|-
2|4|6

How could I do this?

I've tried the following but it returns an error:

=query(raw!A1:C, "select 'A & '-' & B & '-' &C")