SQL query for Declined or incomplete submission

I would like to cleanup our submissions after upgrading to 3.3.0-15. Now I can see all the incomplete and declined submissions from years ago and would like to delete them, mainly to see if this would reduce the database size, but also to clean up the editor’s workflow.
I can use the CLI tool deleteSubmissions.php, so I could use a list of submission IDs, but we really have hundreds of them, so I would like to run a database query to get the IDs of the declined or incomplete submissions.

If I go the manual way to record the IDs of the unwanted submissions (not keen on that since I can write a number wrong), I can turn on a filter in the dashboard for incomplete submissions, but for the declined submissions there is no filter, so I would have to dig them out using SQL queries:

ETA: There is a discussiion about deleting incomplete submissions here, even found a promising tool deleteIncompleteSubmissions.php, but unfortunately it seems to work in 3.4 codebase.