Identifying patterns in a string & replacing all characters with 1st digit

Question

Morning folks. Interesting problem on hand. I have a situation where I have a varchar2 text field where I have different paterns of a sequence of numbers somewhere in the string. I guess, I could write a function where by I accept the whole string and then identify one of the patters below and then finally replace only the recognized pattern with the first digit all the way through to the end of that pattern.
The catch here is that there could be free text before and after the string but there will be spaces when free text ends and the patern begins.
Here are a few patterns I would be interested in. The MAX length is 19 as in Cases 1 and 3.
1. 9999 9999 9999 9999
2. 9999999999999999
3. 9999-9999-9999-9999
4. 9999-9999-99-99999
5. 9999-999999-99999So, here would be an example of the problem in hand :
Call received on 9/22/2009.
5123-4532-8871-9876
Please follow up by 10/22/2009So, the desired output would be :
Call received on 9/22/2009.
5555-5555-5555-5555
Please follow up by 10/22/2009Any ideas ? I am stumped at the fact of before and after text in the string, hence the question for you guys !
Thanks !

Answer 1

Here is another solution. However there has to be a better way! (I'm not a regular expression expert).
SQL> WITH test_data AS
  2  (
  3          SELECT 'Call received on 9/22/2009.
  4          1232 3456 8765 3456
  5          Please follow up by 10/22/2009' AS DATA FROM DUAL UNION ALL
  6          SELECT 'Call received on 9/22/2009.
  7          1232345687653456
  8          Please follow up by 10/22/2009' AS DATA FROM DUAL UNION ALL
  9          SELECT 'Call received on 9/22/2009.
10          1232-3456-8765-3456
11          Please follow up by 10/22/2009' AS DATA FROM DUAL UNION ALL
12          SELECT 'Call received on 9/22/2009.
13          1232-3456-86-3456
14          Please follow up by 10/22/2009' AS DATA FROM DUAL UNION ALL
15          SELECT 'Call received on 9/22/2009.
16          1232-345687-3456
17          Please follow up by 10/22/2009' AS DATA FROM DUAL
18  ), substring AS
19  (
20          SELECT  DATA AS SOURCE
21          ,       REGEXP_INSTR
22                  (
23                          DATA
24                  ,       '(([[:digit:]])+[[:space:]|-]){1,}'
25                  ) AS PATSTART
26          ,       REGEXP_SUBSTR
27                  (
28                          DATA
29                  ,       '(([[:digit:]])+[[:space:]|-]){1,}'
30                  ) AS PATTERN
31          ,       19 AS MAXLENGTH
32          FROM    test_data
33  )
34  SELECT  SUBSTR
35          (
36                  SOURCE
37          ,       1
38          ,       PATSTART-1
39          ) ||
40          TRANSLATE
41          (
42                  PATTERN
43          ,       '0123456789'
44          ,       LPAD
45                  (
46                          SUBSTR
47                          (
48                                  PATTERN
49                          ,       1
50                          ,       1
51                          )
52                  ,       10
53                  ,       SUBSTR
54                          (
55                                  PATTERN
56                          ,       1
57                          ,       1
58                          )
59                  )
60          ) ||
61          SUBSTR
62          (
63                  SOURCE
64          ,       PATSTART + MAXLENGTH
65          )       AS NEW_STRING
66  FROM substring
67  /
NEW_STRING
Call received on 9/22/2009.
        1111 1111 1111 1111
        Please follow up by 10/22/2009
Call received on 9/22/2009.
        1111111111111111
      Please follow up by 10/22/2009
Call received on 9/22/2009.
        1111-1111-1111-1111
        Please follow up by 10/22/2009
Call received on 9/22/2009.
        1111-1111-11-1111
       Please follow up by 10/22/2009
Call received on 9/22/2009.
        1111-111111-1111
      Please follow up by 10/22/2009
SQL>