SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function substring (children 1)
     ExpressionList (children 3)
      Function toFixedString (children 1)
       ExpressionList (children 2)
        Function materialize (children 1)
         ExpressionList (children 1)
          Literal \'hello\'
        Literal UInt64_16
      Literal UInt64_1
      Literal UInt64_8