Forum: Ruby on Rails activerecord issues with rails 3 postgresql

i have one query
@recommendations =
Recommendation.select('cnames.name,max(recommendations.count)').
                  where('recommendations.skill= ?',@key).
                  order('recommendations.company_id ASC').
                  group('recommendations.company_id').
                  joins('JOIN recommendations ON cnames.id =
recommendations.company_id')

when i run this query i got this error

*PG::Error: ERROR:  table name "recommendations" specified more than 
once*

Why it shows like that?

On Wednesday, 27 June 2012 10:13:16 UTC-4, amruby wrote:
> when i run this query i got this error
>
> *PG::Error: ERROR:  table name "recommendations" specified more than once*
>
> Why it shows like that?
>

Since you're querying on the Recommendation model, there's already a 
'FROM
recommendations' clause in the generated query. You probably meant 
'cnames'
in that joins call.

You'll also run into Postgres's rules about using ungrouped values in 
the
SELECT part; the above query won't be legal even with a correct join.

--Matt Jones