Delete some caldav entries over the mysql cmd


I have in the last days some problems with the caldav sync.
The problem isn’t a owncloud issue.
But I would like to clean my calender over the cmd line.

So I would like to execute a command to delete all entries in my personal calendar with contain “Geburtstag von XY”. So I know how I do this with mysql. But sabredav and caldav is very special formated in the mysql db.

Can anyone help me to create a command to delete some entries over the mysql cmd?
Or have anyone a better idea for this problem?