A query without a sub-query: can we do it?

dear all,

i've following table named lab with user_id, lab_id as the PK:

select * from lab;

USER_ID LAB_ID
---------- ----------

         2          1
         2          2
         2          3
         9          3
         9          4
         9          5
         9          6

now i wanna see all the labs where user_id 2 is a member except for the labs where 9 is a member as well, then i'd say:

select * from lab
where user_id = 2
and lab_id not in (select lab_id from lab where user_id = 9);

that results in:
USER_ID LAB_ID
---------- ----------

         2          1
         2          2

and rightly so. user_id 2 belongs to lab 1, 2 and 3. lab 3 has not been selected 'cas user 9 is a member of this lab. great!

now my question is: can i write the same query without having to use the sub-query as i've done above? if yeah, how? theoratically speaking is there *always* an equivilant SQL statement for every query that uses with sub-query?

thanks in advance for any help.

:) ATTA

--

getting the meanin' of data...


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