what is wrong in query

From: Harvinder Singh <Harvinder.Singh_at_MetraTech.com>
Date: Tue, 11 Sep 2001 21:10:25 -0700
Message-ID: <F001.0038A125.20010911084027@fatcity.com>

Hi,
I have a table t_acc_usage having column tx_batch defined as raw(16)......
when i am running the following code i am getting error:

SELECT ( (SELECT count(usage.id_sess) from t_acc_usage usage WHERE usage.tx_batch = hex_to_raw (ltrim('%%VARBIN_BATCH_ID%%', '0x')) + ( SELECT count(error.id_sess)
FROM t_pv_error error WHERE error.c_tx_batch = N'%%STRING_BATCH_ID%%')) ) AS committed_count FROM dual

WHERE usage.tx_batch = hex_to_raw (ltrim('%%VARBIN_BATCH_ID%%', '0x')) + *
ERROR at line 2:
ORA-00932: inconsistent datatypes
what is wrong in query......
Thanks
-Harvinder Received on Tue Sep 11 2001 - 23:10:25 CDT