SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 3)
   ExpressionList (children 3)
    Identifier x
    Identifier u
    Identifier s
   TablesInSelectQuery (children 1)
    TablesInSelectQueryElement (children 1)
     TableExpression (children 1)
      TableIdentifier parallel_replicas_backup
   ExpressionList (children 3)
    OrderByElement (children 1)
     Identifier x
    OrderByElement (children 1)
     Identifier u
    OrderByElement (children 1)
     Identifier s