How can I get an INSTR for a field of datatype long

Hi, how can I get an INSTR for a field of datatype long.

create table mytable
(
Iamlong long
)

SELECT SUBSTR (Iamlong, 3,4) "Substring"
FROM mytable;
This select is not working

Thanks you

LONG is a very difficult datatype to work with. You can write a function to help with getting some of the data out. See here as an example https://www.tek-tips.com/viewthread.cfm?qid=1666677.

If you can, rebuild that table with some other datatype. VARCHAR2, CLOB, or BLOB. You'll save yourself a lot of headache later.