AlterQuery  t_proj_external_agg (children 2)
 ExpressionList (children 1)
  AlterCommand ADD_PROJECTION (children 1)
   Projection (children 1)
    ProjectionSelectQuery (children 2)
     ExpressionList (children 4)
      Identifier k1
      Identifier k2
      Identifier k3
      Function sum (children 1)
       ExpressionList (children 1)
        Identifier value
     ExpressionList (children 3)
      Identifier k1
      Identifier k2
      Identifier k3
 Identifier t_proj_external_agg
