> Not sure what your use is - but if you have t1.id_t2 defined as a 
> foreign key with cascading deletes, then you can never have a t2.id null 
> and any delete of t1 will cascade and automatically delete the 
> associated records in t2.


Thanks for answer! Probably I wasn't clear enough... here's an example:

table "cars"
fields = id, car_name, id_driver

table "drivers"
fields = id, driver_name

table "cars" has a FK to table "drivers"
... foreign key (id_driver) references drivers(id)...

Now I want to delete all cars that *has* a record in "drivers", but the 
driver_name is null

so far, I always do

delete from cars 
where
 (
  select drivers.driver_name 
  from drivers 
  where
  cars.id_drivers = drivers.id
  )
  is null

that works fine, but I just wander if there is a better way... just for 
curiosity...

thanks!!

-s

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