Oracle 10g Update logic.

Question

Hi Guys, I have a table table_ref with Ref column 400 charaters long. I have a request to update this column, basically change one thing in the column. The column has value *'ELBOW, 90-DEGREE, LONG RADIUS;_; ASME B16.9; BEVELED END; SCHEDULE 10S; STAINLESS STEEL, ASTM A403 GR WP3046WX/WP304LWX (DL-STPD) IMPACT TSD, CRYO SERV'*
The requirement is to update this table and remove the *6* from WP3046WX to make it read WP304WX
Update table_ref
Set ref = 'ELBOW, 90-DEGREE, LONG RADIUS;_; ASME B16.9; BEVELED END; SCHEDULE 10S; STAINLESS STEEL, ASTM A403 GR WP304WX/WP304LWX (DL-STPD) IMPACT TSD, CRYO SERV'
where 1= 1.
Please note that the 6 has been removed, but I am not clear on how to do this. I know am going to be using substr, instr etc, but I cannot wrap my head around it.
Thank You

Answer 1

Hi,
You could do that using SUBSTR and INSTR, but, as you discovered, it isn't easy.
Here's a much better way:
UPDATE  table_ref
SET     ref     = REPLACE ( ref
                   , 'WP3046WX'
                 , 'WP304WX'
WHERE   ref     LIKE '%WP3046WX%
;REPLACE (str, x, y)       returns a copy of str, but with all occurences of the sub-sting x changed to y. You don't need to know exactly where x occurs, or how many times.