SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 4)
   ExpressionList (children 3)
    Identifier a
    Function sum (children 1)
     ExpressionList (children 1)
      Identifier c
    Function avg (children 1)
     ExpressionList (children 1)
      Identifier d
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier pk_order
   ExpressionList (children 1)
    Identifier a
   ExpressionList (children 1)
    OrderByElement (children 1)
     Identifier a
