Mass Delete posts by username

I have spammers posting junk on my forum in multiple forum rooms and sometimes it takes me awhile before I notice. How do I mass-delete all their posts?

I've been manually searching by the spammer's username in my browser and then deleting the posts one at a time. Very tedious.

I'm on SQL Server, so I could write an SQL query to delete the user's posts from the main entry table (tblThread), but I'm not sure if there are any dependencies with other tables.
 i.e. here's an SQL query that just deletes from tblThread:
delete * from tblThread where Author_ID=<spammer's userID #>

I'm surprised this mass delete ability by username isn't part of the forum administation. I'm running 7.9

Any recommendations? Is there a plugin to do this? Or does anyone know the exact SQL query to delete from the multiple tables by username?

Be very very very careful with this!  Just imagine if you you are user 42 and the spammer is user 52,  and you accidentally deleted user 42!  Opps!