Here is a simple request:
Visit.group("user_id")
And I get:
PGError: ERROR: column "visits.id" must appear in the GROUP BY clause or be used in an aggregate function
If I add visits.id to the group by clause, then it asks me to add another column, then another, then another. Basically I have to list all columns in the table!
What's going wrong? From the Rails guide it seemed straightforward.
Thanks for your help
Eureka!
The docs are incomplete. I obviously need to add a count, sum, etc method for the grouping to make sense.
I checked my install and received the same results. Looks like a PostgreSQL syntax thing. I'm new to PostgreSQL and have not looked at group by SQL syntax.
Off the top of my head, as a (non recommended) work around, you could insert a .select() with a column list, and it should work. That, however, is a bad solution for obvious reasons, but might work in a pinch.
I tried, and received the same result:
User.group(:first_name)
The following worked:
User.select(:first_name).group(:first_name)
Actually, as I think about it, you shouldn't have a Select * in a Group By? You should select the column(s) you want to aggregate.
Check this out:
I tried, and received the same result:
User.group(:first_name)
The thing is, we group for a reason. So PostgreSQL is expecting that reason to appear, e.g: count(), sum(), etc.