gistfile1.rb

module Hobo
  module Scopes
    class ScopeBuilder


      def exists_sql_condition(reflection, any=false)
        owner = @klass
        owner_primary_key = "#{owner.table_name}.#{owner.primary_key}"

        if reflection.options[:through]
          join_table   = reflection.through_reflection.klass.table_name
          owner_fkey   = reflection.through_reflection.primary_key_name
          conditions   = reflection.options[:conditions].blank? ? '' : " AND #{reflection.through_reflection.klass.send(:sanitize_sql_for_conditions, reflection.options[:conditions])}"

          if any
            "EXISTS (SELECT * FROM #{join_table} WHERE #{join_table}.#{owner_fkey} = #{owner_primary_key}#{conditions})"
          else
            source_fkey  = reflection.source_reflection.primary_key_name
            "EXISTS (SELECT * FROM #{join_table} " +
              "WHERE #{join_table}.#{source_fkey} = ? AND #{join_table}.#{owner_fkey} = #{owner_primary_key}#{conditions})"
          end
        else
          foreign_key = reflection.primary_key_name
          related     = reflection.klass
          conditions  = reflection.options[:conditions].blank? ? '' : " AND #{reflection.klass.send(:sanitize_sql_for_conditions, reflection.options[:conditions])}"

          if any
            "EXISTS (SELECT * FROM #{related.table_name} " +
              "WHERE #{related.table_name}.#{foreign_key} = #{owner_primary_key}#{conditions})"
          else
            "EXISTS (SELECT * FROM #{related.table_name} " +
              "WHERE #{related.table_name}.#{foreign_key} = #{owner_primary_key} AND " +
              "#{related.table_name}.#{related.primary_key} = ?#{conditions})"
          end
        end
      end


    end
  end
end