pl/sql function to parse string to token in oracle - oracle

Question

I have written this code
Select replace (upper(substr(div_no,1,3), ',' ','',''')
from dual
I want when user write div_no like this ('v0e200,q0e600') must return
v0e,q0e
If I have a string like 's05200 , s02700' I want to take first three characters, like 's05 ',' s02'

Answer 1

It seems you're looking for the translate() function :
SQL> select translate ('vwe200,qwe600', ',1234567890', ',')
2 from dual;
TRANSLA
-------
vwe,qwe
SQL>
So your revised test data clarifies the requirement. Here is a regex solution for extracting the first three characters from each segment of a string:
SQL> with testdata as (
2 select 'vwe200,qwe600' as str from dual union all
3 select 's05200 , e0300' as str from dual
4 )
5 select regexp_replace(str, '([a-z0-9]{3})([a-z0-9]*)(,?)','\1\3')
6 from testdata;
REGEXP_REPLACE(STR,'([A-Z0-9]{3})([A-Z0-9]*)(,?)','\1\3')
--------------------------------------------------------------------------------
vwe,qwe
s05 , e03
SQL>
If removing the trailing spaces is required it can be done by adjusting the regex pattern :
SQL> with testdata as (
2 select 'vwe200,qwe600' as str from dual union all
3 select 's05200 , e0300' as str from dual
4 )
5 select regexp_replace(str, '( *)([a-z0-9]{3})([a-z0-9 ]*)(,?)','\2\4')
6 from testdata;
REGEXP_REPLACE(STR,'([A-Z0-9]{3})([A-Z0-9]*)(,?)','\1\3')
--------------------------------------------------------------------------------
vwe,qwe
s05,e03
SQL>
Injecting additional quotes is a use for the replace() function:
SQL> select replace('s05 , e03', ',', ''',''') from dual;
REPLACE('S0
-----------
s05 ',' e03
SQL>
Use the output from the previous answer as the input for this one.

Answer 2

Oracle 12c Query:
with FUNCTION getFirst3CharsOfDelimitedList(
str IN VARCHAR2
) RETURN VARCHAR2
IS
val VARCHAR2(4000);
i INTEGER := 1;
occ INTEGER := 1;
BEGIN
val := SUBSTR( str, i, 3 );
LOOP
i := INSTR( str, ',', 1, occ );
EXIT WHEN i = 0;
LOOP
EXIT WHEN SUBSTR( str, i + 1, 1 ) <> ' ';
i := i + 1;
END LOOP;
val := val || ',' || SUBSTR( str, i + 1, 3 );
occ := occ + 1;
END LOOP;
RETURN val;
END getFirst3CharsOfDelimitedList;
testdata as (
select 'vwe200,qwe600' as str from dual union all
select 's05200 , e0300' as str from dual
)
SELECT getFirst3CharsOfDelimitedList( str ) FROM testdata;
Output:
GETFIRST3CHARSOFDELIMITEDLIST(STR)
----------------------------------
vwe,qwe
s05,e03