I'm not 100% sure, if the next process is safe or not, so first of all, I ask...
In my company's CiviCRM are more than 3900 Contributions, which should be deleted. These Contributions can be listed as result of a report in CiviReport, but not as result from the SearchBuilder because the query is too difficult for SearchBuilder (with 'NOT IN' clauses etc.).
On the report's page, on the Developer tab I see the SQL query of the report, and I have access to the CiviCRM's database, so I can run this query. I can rewrite the SELECT query to a DELETE query.
Is it safe - after backuping the database - run the DELETE query to delete all unneeded Contributions from the civicrm_contribution table, or it causes database inconsistency?