hive中lead和lag函数的使用
导入数据
select * from bus ;
+-------+-------------+
| name | orderdate |
+-------+-------------+
| jack | 2017-01-01 |
| jack | 2017-02-03 |
| jack | 2017-04-06 |
| jack | 2017-01-05 |
| jack | 2017-01-08 |
| mart | 2017-04-08 |
| mart | 2017-04-09 |
| mart | 2017-04-11 |
| mart | 2017-04-13 |
| neil | 2017-05-10 |
| neil | 2017-06-12 |
| tony | 2017-01-02 |
| tony | 2017-01-04 |
| tony | 2017-01-07 |
+-------+-------------+
1.lead()over()将下一行提到当前行来另起字段
参数lesd(需要调整的字段名,下几行,空余部分用什么补充)over()
select name,orderdate,
lead(orderdate,1,0)over(partition by name order by orderdate)as lead_or
from bus;
+-------+-------------+-------------+
| name | orderdate | lead_or |
+-------+-------------+-------------+
| jack | 2017-01-01 | 2017-02-03 |
| jack | 2017-02-03 | 2017-04-06 |
| jack | 2017-04-06 | 2017-01-05 |
| jack | 2017-01-05 | 2017-01-08 |
| jack | 2017-01-08 | 0 |
| mart | 2017-04-08 | 2017-04-09 |
| mart | 2017-04-09 | 2017-04-11 |
| mart | 2017-04-11 | 2017-04-13 |
| mart | 2017-04-13 | 0 |
| neil | 2017-05-10 | 2017-06-12 |
| neil | 2017-06-12 | 0 |
| tony | 2017-01-02 | 2017-01-04 |
| tony | 2017-01-04 | 2017-01-07 |
| tony | 2017-01-07 | 0 |
+-------+-------------+-------------+
2.lag()over()将上一行提到当前行来另起字段
参数lag(需要调整的字段名,上几行,空余部分用什么补充)over()
select name,orderdate,
lag(orderdate,1,0)over(partition by name order by orderdate)as lag_or
from bus;
```sql
+-------+-------------+-------------+
| name | orderdate | lag_or |
+-------+-------------+-------------+
| jack | 2017-01-01 | 0 |
| jack | 2017-02-03 | 2017-01-01 |
| jack | 2017-04-06 | 2017-02-03 |
| jack | 2017-01-05 | 2017-04-06 |
| jack | 2017-01-08 | 2017-01-05 |
| mart | 2017-04-08 | 0 |
| mart | 2017-04-09 | 2017-04-08 |
| mart | 2017-04-11 | 2017-04-09 |
| mart | 2017-04-13 | 2017-04-11 |
| neil | 2017-05-10 | 0 |
| neil | 2017-06-12 | 2017-05-10 |
| tony | 2017-01-02 | 0 |
| tony | 2017-01-04 | 2017-01-02 |
| tony | 2017-01-07 | 2017-01-04 |
+-------+-------------+-------------+
3.substr获取字符转的某些字符
参数substr(需要截取的字段名,从第几位开始,从第几位结束)
select name,orderdate from sub
where substr(orderdate,1,7)="2017-04";
+----------+---------------+
| sub.name | sub.orderdate |
+----------+---------------+
| jack | 2017-04-06 |
| mart | 2017-04-08 |
| mart | 2017-04-09 |
| mart | 2017-04-11 |
| mart | 2017-04-13 |
+----------+---------------+
