An error in query db node

trying to use the following select query within a query DB node for a custom Oracle data source. Can anyone please suggest where I'm going wrong?

select ROWNUM, APPLICATION_NAME, ENVIRONMENT, OS, INSTANCE_NAME, HOSTNAME from web.vw_oracle_dds_inventory where APPLICATION_NAME='ac!applicationName' and ENVIRONMENT='ac!Environment' order by HOSTNAME

The query returns proper results when used without the where clause but the where clause is causing an issue. I get this error message:

There was a problem during the validation of the SQL statement with the database
The SQL Query is invalid, Invalid column index

OriginalPostID-242840