insert into a table values from another table

I'm trying to insert the values from a lookup table into another table with the 'After record added' event and also add the id of the record I've just added. I've tried this but it doesn't work, any help would be much appreciated.
$sql = "INSERT INTO Certificates (PC_P_id,PC_type,PC_valid_For_weeks,PC_status) values ('".$values[P_id]."',(select CV_type,CV_duration_weeks from Certificate_Values where CV_table='Certificates'),'Pending',)";

CustomQuery($sql);