Using REGEXP_SUBSTR to get key-value pair data - string

Question

I have a column with below values,
User_Id=446^User_Input=L307-60#/25" AP^^
I am trying to get each individual value based on a specified key.
All value after User_Id= until it encounters ^
All value after User_Input= until it encounters ^
I tried for and so far I have this,
SELECT LTRIM(REGEXP_SUBSTR('User_Id=446^User_Input=L307-60#/25" AP^'
,'[0-9]+',1,1),'^') User_Id
from dual
How do I get the value for the User_Input??
P.S: User input can have anything, like ',", *,% including a ^ in the middle of the string (that is, not as a delimiter).
Any help would be greatly appreciated..

Answer 1

This can be easily solved using boring old INSTR to calculate the offsets of the start and end points for the KEY and VALUE strings.
The trick is to use the optional occurrence parameter to identify each the correct instance of =. Because the input can contain carets which aren't intended as delimiters we need to use a negative position to identify the last ^.
with cte as (
select kv
, instr(kv, '=', 1, 1)+1 as k_st -- first occurrence
, instr(kv, '^', 1) as k_end
, instr(kv, '=', 1, 2)+1 as v_st -- second occurrence
, instr(kv, '^', -1) as v_end -- counting from back
from t23
)
select substr(kv, k_st, k_end - k_st) as user_id
, substr(kv, v_st, v_end - v_st) as user_input
from cte
/
Here is the requisite SQL Fiddle to prove it works. I think it's much easier to understand than any regex equivalent.

Answer 2

If there is no particular need to use Regex, something like this returns the value.
WITH rslt AS (
SELECT 'User_Id=446^User_Input=L307-60#/25" AP^' val
FROM dual
)
SELECT LTRIM(SUBSTR(val
,INSTR(val, '=', 1, 2) + 1
,INSTR(val, '^', 1, 2) - (INSTR(val, '=', 1, 2) + 1)))
FROM rslt;
Of course, if you can't guarantee that there will not be any carets that are valid text characters, this will possibly return partial results.

Answer 3

Assuming that you will always have 'User_Id=' and 'User_Input=' in your string, I would use a character group approach to parsing
Use the starting anchor,^, and ending anchor, $. Look for 'User_Id=' and 'User_Input='
Associate the value you are searching for with a character group.
SCOTT#dev>
1 SELECT REGEXP_SUBSTR('User_Id=446^User_Input=L307-60#/25" AP^','^User_Id=(.*\^)User_Input=(.*\^)$',1, 1, NULL, 1) User_Id
2* FROM dual
SCOTT#dev> /
USER
====
446^
SCOTT#dev>
1 SELECT REGEXP_SUBSTR('User_Id=446^User_Input=L307-60#/25" AP^','^User_Id=(.*\^)User_Input=(.*\^)$',1, 1, NULL, 2) User_Input
2* FROM dual
SCOTT#dev> /
USER_INPUT
================
L307-60#/25" AP^
SCOTT#dev>

Answer 4

Got this answer from a friend of mine.. Looks simple and works great...
SELECT
regexp_replace('User_Id=446^User_Input=L307-60#/25" AP^^', '.*User_Id=([^\^]+).*', '\1') User_Id,
regexp_replace('User_Id=446^User_Input=L307-60#/25" AP^^', '.*User_Input=(.*)[\^]$', '\1') User_Input
FROM dual
Posting here just in case any of you find it interesting..