Filtering: SQL Error when no where-clause in query

Adding a filter to a SQL report causes a SQL error if the query does not have a where clause in it.

For example, add a "User field search box" filter on the filter tab and at the bottom of your sql (%%FILTER_USERS:ex.lastname%%).

Sample query:

SELECT *
FROM PREFIX_EXPORT ex
%%FILTER_USERS:ex.lastname%%

This will cause an error:

Error reading from database

More information about this error
Debug info: ORA-00907: missing right parenthesis
SELECT *
FROM (SELECT *
FROM m_EXPORT ex
AND ex.lastname LIKE '%Fisher%')
WHERE rownum <= :o_oracle_num_rows
[array (
'o_oracle_num_rows' => 5000,
)]
Error code: dmlreadexception
Stack trace:

line 423 of /lib/dml/moodle_database.php: dml_read_exception thrown
line 272 of /lib/dml/oci_native_moodle_database.php: call to moodle_database->query_end()
line 1088 of /lib/dml/oci_native_moodle_database.php: call to oci_native_moodle_database->query_end()
line 54 of /blocks/configurable_reports/reports/sql/report.class.php: call to oci_native_moodle_database->get_recordset_sql()
line 86 of /blocks/configurable_reports/reports/sql/report.class.php: call to report_sql->execute_query()
line 67 of /blocks/configurable_reports/viewreport.php: call to report_sql->create_report()

A work-around is to add a "WHERE 1=1":

SELECT *
FROM PREFIX_EXPORT ex
WHERE 1=1
%%FILTER_USERS:ex.lastname%%