Query for records older than 5 days

[tdignan87]

 String deletecommod = db.Query<String>("UPDATE REQUIREMENTSH SET REQUIREMENTSH.DELETED = " + DateTime.Now.ToOADate() + "WHERE REQUIREMENTSH.CREATIONDATE >= DATEADD(day,-5, GETDATE()") .FirstOrDefault();

Hi i have a firebird database which it's datetime format is stored as a DOUBLE.
I cannot change this in the db.

What i need to do is update data in the tables for records older than 5 days. The query above isnt working. I've tried google but no luck. Could anyone help me please?
Thanks
Tom

 

[tdignan87]

REQUIREMENTSH.CREATIONDATE is the double format which i need to run the query for.
Basically need to update any records which are older than 5 days old. Cheers