Comparing Dates in Subqueries

Hi,

I am trying to write a basic select query with a subquery.

select x
from y
where DateTime > '27 January 2003'
and DateTime < '02 February 2003'
and a = 'ttt'
and x IN (SELECT x
from y
WHERE a = 'vvv'
and rcd.DateTime > '27 January 2003'
and rcd.DateTime < '02 February 2003')

I only want to see the data for the records where ttt happened before vvv.

Any ideas?select x
from y
where DateTime > '27 January 2003'
and DateTime < '02 February 2003'
and a = 'ttt'
and exists
(SELECT *
from y y2
WHERE y2.a = 'vvv'
and y2.DateTime > '27 January 2003'
and y2.DateTime < '02 February 2003'
and y2,DateTime > y.DateTime
)|||select y.x
from y
left join
(
select x,MinDateTime=min(DateTime)
from y
where a='vvv' and DateTime > '27 January 2003' and DateTime < '02 February 2003'
group by x
) sy on sy.x=y.x and a='ttt' and ( (DateTime<MinDateTime) or MinDateTime is null )sqlsql