# File lib/thinking_sphinx/adapters/postgresql_adapter.rb, line 12
    def concatenate(clause, separator = ' ')
      if clause[/^COALESCE/]
        clause.split('), ').join(") || '#{separator}' || ")
      else
        clause.split(', ').collect { |field|
          "CAST(COALESCE(#{field}, '') as varchar)"
        }.join(" || '#{separator}' || ")
      end
    end