ROWNUM is a pseudo column that is assigned an incremental unique integer value for records of a table or subselects, beginning with 1.
Exasol implements ROWNUM adhering to the overall SQL semantics.
- ROWNUM cannot be combined with other conditions in the WHERE clause. Anything you put into the WHERE clause of a statement filters input data. To avoid confusion and seemingly wrong results, we only allow ROWNUM in situations where the result is in line with Oracle's semantic.
- ROWNUM cannot be used in combination with the PRIMARY KEY, UNIQUE, and FOREIGN KEY statements.