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reverse nvarchar [message #181269]

Fri, 07 July 2006 17:22

stacdab
Messages: 4
Registered: July 2006

Junior Member

Hello all.

Does anyone how to get around this problem? We need to reverse nvarchar strings.

SQL> select reverse('abcdefg'), reverse(n'abcdefg') from dual;

REVERSE REVERSE
------- -------
gfedcba ┐┐┐┐┐┐┐

Thanks.

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Re: reverse nvarchar [message #181286 is a reply to message #181269]

Sat, 08 July 2006 04:04

Maaher
Messages: 7065
Registered: December 2001

Senior Member

Ouch, of all the Oracle functions you choose the one that is not documented. What happens if you write your own 'nvarchar reverse'?

CREATE OR REPLACE FUNCTION n_reverse(p_str IN NVARCHAR2)
RETURN NVARCHAR2
AS
  v_return NVARCHAR2(4000);
BEGIN
  FOR i in 1..length(p_str)
  LOOP
    v_return := SUBSTR(p_str,i,1)||v_return;
  END LOOP;

  RETURN v_return;
END n_reverse;

You can add the DETERMINISTIC keyword (you don't access any database objects) but I don't think you'd see any performance increase.

A second option:

select reverse('abcdefg'), reverse(to_char(n'abcdefg')) from dual;

Like I said: REVERSE is the one Oracle SQL function that is not documented but apparently NVARCHAR is not supported.

MHE

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Re: reverse nvarchar [message #181304 is a reply to message #181286]

Sat, 08 July 2006 06:46

stacdab
Messages: 4
Registered: July 2006

Junior Member

Thanks for the help. I guess we'll have to roll our own.

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