Write error log to other file on executing a .SQl file from shell script

I am executing a sql script 'test.sql ' from shell script. Script 'test.sql' writes output to a flat file using spool.

'test.sql' body is similar like
spool /root/test.inl
select * from dual;
spool off
exit

I want to ensure whether it has run succesfully, if not write log error to some test.log file.
Currently it is writting output and error in same file i.e in test .inl

Kindly help me out to collect error log seperatly asap.
Thanks