group by - oracle query to get max hour every day, and corresponding row values -

i'm having hard time creating query following:

i have table, called log:

id | insert_time             | log_value ----------------------------------------  1 | 2013-04-29 18:00:00.000 | 160473  2 | 2013-04-29 21:00:00.000 | 154281  3 | 2013-04-30 09:00:00.000 | 186552  4 | 2013-04-30 14:00:00.000 | 173145  5 | 2013-04-30 14:30:00.000 | 102235  6 | 2013-05-01 11:00:00.000 | 201541  7 | 2013-05-01 23:00:00.000 | 195234 

what want build query returns, each day, last values inserted (using max value of insert_time). i'm interested in date part of column, , in column log_value. so, resultset after running query:

2013-04-29  154281 2013-04-30  102235 2013-05-01  195234 

i guess need use group on insert_time column, along max() function, doing that, can't seem log_value. can me on this, please?

(i'm on oracle 10g)

select trunc(insert_time),        log_value   (     select insert_time,            log_value,            rank() on (partition trunc(insert_time)                             order insert_time desc) rnk       log)  rnk = 1 

is 1 option. uses analytic function rank identify row latest insert_time on each day.