SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 5)
   ExpressionList (children 2)
    Function toString (children 1)
     ExpressionList (children 1)
      Identifier d
    Function avg (children 1)
     ExpressionList (children 1)
      Identifier a
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier pk_order
   ExpressionList (children 1)
    Function toString (children 1)
     ExpressionList (children 1)
      Identifier d
   ExpressionList (children 1)
    OrderByElement (children 1)
     Function toString (children 1)
      ExpressionList (children 1)
       Identifier d
   Literal UInt64_5
