Why are we getting the ORA-01795 error in BI Publisher?

The error indicates that there are too many values defined in the SQL filter for a given expression.

The option to pass more than one value to BIP SQL via bind parameters makes reports very flexible and versatile. However, BI Publisher doesn't limit the number of passed values, and it could generate a SQL with very large number of IN-LIST values, possibly hitting the internal Oracle limit of maximum 1,000 IN-LIST values.

Please review the recommendations in this support document and adjust your query accordingly: Oracle Business Intelligence Publisher Performance Recommendations for Fusion Cloud Applications.