Can I use EXISTS?

Question

Hi, I am fairly new to sql and need help with a query...
I have two tables
Titles
Name.............Number
A...................1
B...................2
C...................3
D...................4
etc
etc
Holders
Number.........Colour
1...................Blue
2...................Red
3...................Green
etc
I want to selct all from Titles where the number does not exist within holders.number. My simple query is
Select Titles.*
where Titles.Number = Holders.Number
and Titles.Number not in (select Number from Holders)
However, both table have > 50000 records and the query takes too long to run. How can I do this using NOT EXISTS?
Thanks,
Ian

Answer 1

Your two choices would look something like this...
Select Titles.*
from   Titles
where  Titles.Num_ber not in (select Num_ber
                              from   Holders
                              where  num_ber is not null);
Select Titles.*
from   Titles
where  NOT EXISTS (select 1
                   from   holders
                   where  holders.num_ber = titles.num_ber)
;Run some explain plans and benchmarks to see if one is faster than the other.