visit_Arel_Nodes_SelectStatement

# File activerecord/lib/arel/visitors/oracle.rb, line 8
        def visit_Arel_Nodes_SelectStatement(o, collector)
          o = order_hacks(o)

          # if need to select first records without ORDER BY and GROUP BY and without DISTINCT
          # then can use simple ROWNUM in WHERE clause
          if o.limit && o.orders.empty? && o.cores.first.groups.empty? && !o.offset && o.cores.first.set_quantifier.class.to_s !~ /Distinct/
            o.cores.last.wheres.push Nodes::LessThanOrEqual.new(
              Nodes::SqlLiteral.new("ROWNUM"), o.limit.expr
            )
            return super
          end

          if o.limit && o.offset
            o        = o.dup
            limit    = o.limit.expr
            offset   = o.offset
            o.offset = nil
            collector << "
                SELECT * FROM (
                  SELECT raw_sql_.*, rownum raw_rnum_
                  FROM ("

            collector = super(o, collector)

            if offset.expr.is_a? Nodes::BindParam
              collector << ") raw_sql_ WHERE rownum <= ("
              collector = visit offset.expr, collector
              collector << " + "
              collector = visit limit, collector
              collector << ") ) WHERE raw_rnum_ > "
              collector = visit offset.expr, collector
              return collector
            else
              collector << ") raw_sql_
                  WHERE rownum <= #{offset.expr.to_i + limit}
                )
                WHERE "
              return visit(offset, collector)
            end
          end

          if o.limit
            o       = o.dup
            limit   = o.limit.expr
            collector << "SELECT * FROM ("
            collector = super(o, collector)
            collector << ") WHERE ROWNUM <= "
            return visit limit, collector
          end

          if o.offset
            o        = o.dup
            offset   = o.offset
            o.offset = nil
            collector << "SELECT * FROM (
                  SELECT raw_sql_.*, rownum raw_rnum_
                  FROM ("
            collector = super(o, collector)
            collector << ") raw_sql_
                )
                WHERE "
            return visit offset, collector
          end

          super
        end