I want to return the following position from the strings using REGEXP_INSTR.
I am looking for the word car with exact match in the following strings.
car,care,oscar - 1
care,car,oscar - 6
oscar,care,car - 12
something like
SELECT REGEXP_INSTR('car,care,oscar', 'car', 1, 1) "REGEXP_INSTR" FROM DUAL;
I am not sure what kind of escape operators to use.
A simpler solution is to surround the source string and search string with commas and find the position using INSTR.
SELECT INSTR(',' || 'car,care,oscar' || ',', ',car,') "INSTR" FROM DUAL;
Example:
with x(y) as (
SELECT 'car,care,oscar' from dual union all
SELECT 'care,car,oscar' from dual union all
SELECT 'oscar,care,car' from dual union all
SELECT 'car' from dual union all
SELECT 'cart,care,oscar' from dual
)
select y, ',' || y || ',' , instr(',' || y || ',',',car,')
from x
| Y | ','||Y||',' | INSTR(','||Y||',',',CAR,') |
|-----------------|-------------------|----------------------------|
| car,care,oscar | ,car,care,oscar, | 1 |
| care,car,oscar | ,care,car,oscar, | 6 |
| oscar,care,car | ,oscar,care,car, | 12 |
| car | ,car, | 1 |
| cart,care,oscar | ,cart,care,oscar, | 0 |
The following query handles all scenarios. It returns the starting position if the string begins with car, or the whole string is just car. It returns the starting position + 1 if ,car, is found or if the string ends with ,car to account for the comma.
SELECT
CASE
WHEN REGEXP_LIKE('car,care,oscar', '^car,|^car$') THEN REGEXP_INSTR('car,care,oscar', '^car,|^car$', 1, 1)
WHEN REGEXP_LIKE('car,care,oscar', ',car,|,car$') THEN REGEXP_INSTR('car,care,oscar', ',car,|,car$', 1, 1)+1
ELSE 0
END "REGEXP_INSTR"
FROM DUAL;
SQL Fiddle demo with the various possibilities
I like Noel his answer as it gives a very good performance! Another way around is by creating separate rows from a character separated string: pm.nodes = 'a;b;c;d;e;f;g'
(select regexp_substr(pm.nodes,'[^;]+', 1, level)
from dual
connect by regexp_substr(pm.nodes, '[^;]+', 1, level) is not null)
