Query for open Tasks associated with Opportunities owned by specific user

[tennvol88]

Is it possible to construct a SOQL query that will retrieve all of the open Tasks associated with Opportunities owned by a specific user?  I tried using the 'What' relationship for the Task like this:

SELECT Id, WhoId, WhatId, Status, Subject FROM Task WHERE IsClosed = 'false' AND What.OwnerId = '<some id>'

but the query fails on the What.OwnerId condition.  Apparently only What.Name is valid.  Any thoughts?

[j020]

Check ownerid = id

[tennvol88]

That just gives me the Id of the associated Opportunity which is already available as WhatId.