sql query to get data between two dates

[ciba]

I need to write an SQL query for the same ..

I am ableto retrive values between two dates '2009-07-15' and '2009-07-16' but
not when the two dates are same but time is different....

select * from tbl_abc where trunc(StartTime) between to_date('2009-07-15', 'YYYY-MM-DD') and to_date('2009-07-16', 'YYYY-MM-DD');

but this will not work for same dates ....