Decoding- best way to decode characters to numbers using a conversion table

Question

I have input string which mostly contains numbers, but at the end there are 2 characters which means a country code, like 'EE' for estonia, or 'LV' for latvia and so on, see example input value:
select '9999123456789012EE00' input, null output from dual;I want into column Output to put value where those 2 characters are decoded/replaced with numbers with following algorithm:
1. replace in input string 9999123456789012EE00 characters with numbers 14 and 14 so the output would be 9999123456789012141400.
2. The 14 was for specially letter 'E', all alphabet is encoded like following:
A=10
B=11
C=12
D=13
E=14
Y=34
Z=35
So, value "9999123456789012LV00" should be converted into 9999123456789012213100 (L = 21, V =31).
What is the best way to achieve such decoding in plsql/sql?
Edited by: CharlesRoos on Mar 16, 2010 3:52 AM

Answer 1

Thx, Seems very nice.
with t as (
  select '9999123456789012LV00' input from dual 
  union all
  select '9999123456789012AA00' input from dual
  union all
  select '9AA99912345678901200' input from dual
select input,
       regexp_replace (input,  '[[:alpha:]]+',
                       (ascii (regexp_substr (input, '[[:alpha:]]')) - 55) || (ascii (regexp_substr (input, '[[:alpha:]]',1,2)) - 55))output
from t
9999123456789012LV00     9999123456789012213100
9999123456789012AA00     9999123456789012101000
9AA99912345678901200     9101099912345678901200
;