Question

I’m trying to put a where clause in a select distinct query in postgresql but having no luck.

I want to do the following:

select distinct on (state_or_county) state_or_county 
from locations 
where country = "USA"

I’ve done this many times in mysql and can’t understand why this isn’t working.

Can someone please correct the query? Or explain just why it isn’t working?

Answer 1

In postgresql a string literal must be wrapped in single quotes:

select distinct on (state_or_county) state_or_county 
from locations 
where country = 'USA'

Double quotes are used for identifiers, if needed:

select distinct on ("state_or_county") "state_or_county" 
from "locations" 
where "country" = 'USA'