SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function tokens (children 1)
     ExpressionList (children 3)
      Literal \'a\'
      Literal \'ngrams\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal UInt64_1
