how to select distinct records

i have a table like one shown below

start_date | end_date | traveller

1/1/2005   |  10/10/2005 |   a
1/1/2005   |  10/10/2005 |   b
5/1/2005   |  11/10/2005 |   c
2/1/2005   |   6/11/2005 |   d
3/1/2005   |  11/23/2005 |   e
3/1/2005   |  11/23/2005 |   f

I need to write a query that would give me only one record for any distinct date range. My results should be something like

select distinct start_date, end_date, (first traveller found for that start_date and end_date) from table;

start_date | end_date | traveller

1/1/2005   |  10/10/2005 | a
5/1/2005   |  11/10/2005 | c
2/1/2005   |   6/11/2005 | d
3/1/2005   |  11/23/2005 | e

or

start_date | end_date | traveller

1/1/2005   |  10/10/2005 | b
5/1/2005   |  11/10/2005 | c
2/1/2005   |   6/11/2005 | d
3/1/2005   |  11/23/2005 | f

As you see I dont care about which traveller is returned for a particular date range (1/1/2005 - 10/10/2005) if it returns 'a' or 'b'. All i need is one record per date range.

I know I can write a function that takes the start and end_date as parameters and returns the first record found by using the rownum, but is there a way to do this in plain SQL ?

Thanks in advance,
Wally Received on Thu Nov 10 2005 - 19:18:29 CST