SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 2)
   ExpressionList (children 1)
    Literal \'number: 3\' (alias s)
   ExpressionList (children 1)
    Function extract (children 1)
     ExpressionList (children 2)
      Identifier s
      Literal \'\\\\d+\'