SelectWithUnionQuery (children 1)
 ExpressionList (children 1)
  SelectQuery (children 1)
   ExpressionList (children 1)
    Function substring (children 1)
     ExpressionList (children 3)
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal \'clickhouse\'
      Function materialize (children 1)
       ExpressionList (children 1)
        Literal UInt64_2
      Literal Int64_-2