mysql怎么实现的lead和lag函数功能
本篇内容主要讲解“MySQL怎么实现的lead和lag函数功能”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“mysql怎么实现的lead和lag函数功能”吧!
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MariaDB [test]> select * from t;
+--------------------------------------+---------------------+
| case_id | assigned_date |
+--------------------------------------+---------------------+
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-18 14:08:14 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d51 | 2016-05-18 14:25:22 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-18 14:26:01 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-19 07:19:13 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-19 07:53:09 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d51 | 2016-05-19 08:18:01 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-19 12:12:35 |
+--------------------------------------+---------------------+
7 rows in set (0.00 sec)
MariaDB [test]> SELECT t1.case_id, t1.assigned_date,
-> (SELECT t2.assigned_date
-> FROM t AS t2
-> WHERE t2.case_id = t1.case_id AND
-> t2.assigned_date > t1.assigned_date
-> ORDER BY t2.assigned_date LIMIT 1) AS next_date,
-> (SELECT t2.assigned_date
-> FROM t AS t2
-> WHERE t2.case_id = t1.case_id AND
-> t2.assigned_date < t1.assigned_date
-> ORDER BY t2.assigned_date DESC LIMIT 1) AS prev_date
-> FROM t AS t1;
+--------------------------------------+---------------------+---------------------+---------------------+
| case_id | assigned_date | next_date | prev_date |
+--------------------------------------+---------------------+---------------------+---------------------+
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-18 14:08:14 | 2016-05-18 14:26:01 | NULL |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d51 | 2016-05-18 14:25:22 | 2016-05-19 08:18:01 | NULL |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-18 14:26:01 | 2016-05-19 07:19:13 | 2016-05-18 14:08:14 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-19 07:19:13 | 2016-05-19 07:53:09 | 2016-05-18 14:26:01 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-19 07:53:09 | 2016-05-19 12:12:35 | 2016-05-19 07:19:13 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d51 | 2016-05-19 08:18:01 | NULL | 2016-05-18 14:25:22 |
| 41c19f76-e52e-c4c9-62c2-573c71ec5d50 | 2016-05-19 12:12:35 | NULL | 2016-05-19 07:53:09 |
+--------------------------------------+---------------------+---------------------+---------------------+
7 rows in set (0.01 sec)
到此，相信大家对“mysql怎么实现的lead和lag函数功能”有了更深的了解，不妨来实际操作一番吧！这里是创新互联网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
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