sql 中的导航函数 FIRST_VALUE, LAST_VALUE
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sql 中的导航函数 FIRST_VALUE, LAST_VALUE
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FIRST_VALUE 以下示例計算各部門的最快時間,并且計算某個部門么每個員工與第一名的時間差
WITH finishers AS(SELECT 'Sophia Liu' as name,TIMESTAMP '2016-10-18 2:51:45' as finish_time,'F30-34' as divisionUNION 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 ASCROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS fastest_timeFROM finishers);| 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 以下示例計算各部門的最慢的時間,并且計算某個部門么每個員工與最后一名的時間差
WITH finishers AS(SELECT 'Sophia Liu' as name,TIMESTAMP '2016-10-18 2:51:45' as finish_time,'F30-34' as divisionUNION 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 ASCROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS slowest_timeFROM finishers);| 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 |
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