sql 中的导航函数 FIRST_VALUE， LAST_VALUE

FIRST_VALUE 以下示例计算各部门的最快时间，并且计算某个部门么每个员工与第一名的时间差

WITH finishers AS
 (SELECT 'Sophia Liu' as name,
  TIMESTAMP '2016-10-18 2:51:45' as finish_time,
  'F30-34' as division
  UNION ALL SELECT 'Lisa Stelzner', TIMESTAMP '2016-10-18 2:54:11', 'F35-39'
  UNION ALL SELECT 'Nikki Leith', TIMESTAMP '2016-10-18 2:59:01', 'F30-34'
  UNION ALL SELECT 'Lauren Matthews', TIMESTAMP '2016-10-18 3:01:17', 'F35-39'
  UNION ALL SELECT 'Desiree Berry', TIMESTAMP '2016-10-18 3:05:42', 'F35-39'
  UNION ALL SELECT 'Suzy Slane', TIMESTAMP '2016-10-18 3:06:24', 'F35-39'
  UNION ALL SELECT 'Jen Edwards', TIMESTAMP '2016-10-18 3:06:36', 'F30-34'
  UNION ALL SELECT 'Meghan Lederer', TIMESTAMP '2016-10-18 3:07:41', 'F30-34'
  UNION ALL SELECT 'Carly Forte', TIMESTAMP '2016-10-18 3:08:58', 'F25-29'
  UNION ALL SELECT 'Lauren Reasoner', TIMESTAMP '2016-10-18 3:10:14', 'F30-34')
SELECT name,
  FORMAT_TIMESTAMP('%X', finish_time) AS finish_time,
  division,
  FORMAT_TIMESTAMP('%X', fastest_time) AS fastest_time,
  TIMESTAMP_DIFF(finish_time, fastest_time, SECOND) AS delta_in_seconds
FROM (
  SELECT name,
  finish_time,
  division,
  FIRST_VALUE(finish_time)
    OVER (PARTITION BY division ORDER BY finish_time ASC
    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS fastest_time
  FROM finishers);

name	finish_time	division	fastest_time	delta_in_seconds
Carly Forte	03:08:58	F25-29	03:08:58	0
Sophia Liu	02:51:45	F30-34	02:51:45	0
Nikki Leith	02:59:01	F30-34	02:51:45	436
Jen Edwards	03:06:36	F30-34	02:51:45	891
Meghan Lederer	03:07:41	F30-34	02:51:45	956
Lauren Reasoner	03:10:14	F30-34	02:51:45	1109
Lisa Stelzner	02:54:11	F35-39	02:54:11	0
Lauren Matthews	03:01:17	F35-39	02:54:11	426
Desiree Berry	03:05:42	F35-39	02:54:11	691
Suzy Slane	03:06:24	F35-39	02:54:11	733

FIRST_VALUE 以下示例计算各部门的最慢的时间，并且计算某个部门么每个员工与最后一名的时间差

WITH finishers AS
 (SELECT 'Sophia Liu' as name,
  TIMESTAMP '2016-10-18 2:51:45' as finish_time,
  'F30-34' as division
  UNION ALL SELECT 'Lisa Stelzner', TIMESTAMP '2016-10-18 2:54:11', 'F35-39'
  UNION ALL SELECT 'Nikki Leith', TIMESTAMP '2016-10-18 2:59:01', 'F30-34'
  UNION ALL SELECT 'Lauren Matthews', TIMESTAMP '2016-10-18 3:01:17', 'F35-39'
  UNION ALL SELECT 'Desiree Berry', TIMESTAMP '2016-10-18 3:05:42', 'F35-39'
  UNION ALL SELECT 'Suzy Slane', TIMESTAMP '2016-10-18 3:06:24', 'F35-39'
  UNION ALL SELECT 'Jen Edwards', TIMESTAMP '2016-10-18 3:06:36', 'F30-34'
  UNION ALL SELECT 'Meghan Lederer', TIMESTAMP '2016-10-18 3:07:41', 'F30-34'
  UNION ALL SELECT 'Carly Forte', TIMESTAMP '2016-10-18 3:08:58', 'F25-29'
  UNION ALL SELECT 'Lauren Reasoner', TIMESTAMP '2016-10-18 3:10:14', 'F30-34')
SELECT name,
  FORMAT_TIMESTAMP('%X', finish_time) AS finish_time,
  division,
  FORMAT_TIMESTAMP('%X', slowest_time) AS slowest_time,
  TIMESTAMP_DIFF(slowest_time, finish_time, SECOND) AS delta_in_seconds
FROM (
  SELECT name,
  finish_time,
  division,
  LAST_VALUE(finish_time)
    OVER (PARTITION BY division ORDER BY finish_time ASC
    ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS slowest_time
  FROM finishers);

name	finish_time	division	slowest_time	delta_in_seconds
Carly Forte	03:08:58	F25-29	03:08:58	0
Sophia Liu	02:51:45	F30-34	03:10:14	1109
Nikki Leith	02:59:01	F30-34	03:10:14	673
Jen Edwards	03:06:36	F30-34	03:10:14	218
Meghan Lederer	03:07:41	F30-34	03:10:14	153
Lauren Reasoner	03:10:14	F30-34	03:10:14	0
Lisa Stelzner	02:54:11	F35-39	03:06:24	733
Lauren Matthews	03:01:17	F35-39	03:06:24	307
Desiree Berry	03:05:42	F35-39	03:06:24	42
Suzy Slane	03:06:24	F35-39	03:06:24	0