KeysOnly Function dont return Keys

I experiment a little bit with GAE, but now I have a problem. First of all I store some stuff into the datastore, with an NewIncompleteKey.
So there is the issue. My Website sends timestamps (I handle them as "ID"s) to the back-end. I parse then and want to delete them from the datastore.
I thought I can do this.

type Food struct{
    Id int64
    Course string
    Name string 
    Date string
    Price float64
}

...Some Code...

func deleteEntries(mealsID []string, r *http.Request) int{
	// Get context from 
    c := appengine.NewContext(r);

	
	for _,id := range mealsID{
		var key *datastore.Key = nil
		q := datastore.NewQuery("Meal").Ancestor(mealStoreKey(c)).Filter("Course =", "dessert").KeysOnly()
		_, err := q.GetAll(c, key)
		if err != nil{
			return 0
		}
		log.Printf("Here the keys: %T %v ", key, key)
		log.Printf("%v ", id)
		e := datastore.Delete(c, key)
		if e != nil{
			return 33		
		}		
	}

	return len(mealsID)
}

But it doesn't work, because I get an error at the datastore.Delete() function. Anyone an idea?

Edit:

Part I:

   keys, err := q.GetAll(c, nil)
   …
   err = datastore.DeleteMulti(c, keys)

Thanks to Dave.

Part II:

I passed an String as Filter vaule to the query, but it have to be an Int64 same as in the datastore. Note to my self: You have to pass also the same type of var to the query.

func deleteEntries(mealsID []string, r *http.Request) int{
 // Get context from 
 c := appengine.NewContext(r);


 for _,id := range mealsID{
	 ID,_ := strconv.Atoi(id)
	 q:= datastore.NewQuery("Meal").Ancestor(mealStoreKey(c)).Filter("Id =", ID ).KeysOnly()
	 keys, err := q.GetAll(c, nil)
	 if err != nil{
	 	 return 0
	 }
	 log.Printf("ID: %v ", id)
	 log.Printf("Keys: %v ", keys)
	 e := datastore.DeleteMulti(c, keys)
	 if e != nil{
		 log.Printf("%v ", e)
	       	 return 0		
	 }		
 }

 return len(mealsID)
}

The keys are returned from GetAll. So you should instead write:

keys, err := q.GetAll(c, nil)
…
err = datastore.DeleteMulti(c, keys)

GetAll ignores the dst parameter for keys-only requests – datastore reference. So, in the example above, key will still be set to nil which explains the error.