Question

I am trying to query against an array of strings. The me_topics_users table is an auto-generated table by Rails so to query it, I must use custom SQL.

@topics = self.distributions.map(&:me_topic).compact
ActiveRecord::Base.find_by_sql("SELECT * FROM `me_topics_users` WHERE (me_topic_id IN (#{@topics.join(', ')}))")

But this returns :

NoMethodError: undefined method `abstract_class?' for Object:Class
from /Users/macuser/Sites/hq_channel/vendor/rails/activerecord/lib/active_record/base.rb:2207:in `class_of_active_record_descendant'
from /Users/macuser/Sites/hq_channel/vendor/rails/ac

What am I doing wrong here?

Updated with Substitution but still get the same error

ActiveRecord::Base.find_by_sql(["SELECT * FROM `me_topics_users` WHERE (me_topic_id IN (?) )", @topics.join("', '")])

A simpler version:

ActiveRecord::Base.connection.execute(["SELECT * FROM me_topics_users WHERE me_topic_id= ?", '4'])

returns:

ActiveRecord::StatementInvalid: TypeError: wrong argument type Array (expected String): SELECT * FROM me_topics_users WHERE me_topic_id= ?4
from /Users/macuser/Sites/hq_channel/vendor/rails/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb:212:in `log'
from /Users/macuser/Sites/hq_channel/vendor/rails/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb:320:in `execute'
from (irb):51
from :0

Answer 1

ActiveRecord::Base.connection.execute("SELECT * FROM `me_topics_users` WHERE (me_topic_id IN ('#{@topics.join("', '")}') )")