Oracle 查询合并按 id 分组并按日期排序的多行

Question

我需要帮助来编写此 SQLFiddle 的视图。目前数据如下：

SERIALNUMBER | INSERTDATE           | PARAM1 | PARAM2 | PARAM3 | PARAM4 | PARAM5
3456         | 2017-11-15T12:00:54Z | (null) | (null) | (null) | (null) |  17
3456         | 2017-11-15T12:01:03Z | (null) | (null) |    2   | (null) | (null)
3456         | 2017-11-15T12:07:16Z | (null) | (null) | (null) |    7   | (null)
3456         | 2017-11-15T12:08:08Z | (null) | (null) | (null) | (null) |  19
3456         | 2017-11-15T12:11:32Z |   abc  | (null) | (null) | (null) | (null)
12           | 2017-11-15T12:00:50Z | (null) |    4   | (null) | (null) | (null)
12           | 2017-11-15T12:01:03Z | (null) |    7   | (null) | (null) | (null)
12           | 2017-11-15T12:07:03Z | (null) | (null) | (null) |   te   | (null)

我想要接收的结果是按序列号分组的数据，如果有更多的非空数据分组的列应该选择最新的：

SERIALNUMBER | INSERTDATE           | PARAM1 | PARAM2 | PARAM3 | PARAM4 | PARAM5
3456         | 2017-11-15T12:00:54Z |   abc  | (null) |    2   |    7   |  19
12           | 2017-11-15T12:00:50Z | (null) |    7   | (null) |   te   | (null)

非常感谢您的帮助

Answer 1

你没有为此指定确切的规则，所以我猜你想要最大值。如果是这样，这是一个简单的聚合：

select serialnumber, min(InsertDate) as InsertDate,
       max(Param1) as Param1,
       max(Param2) as Param2,
       max(Param3) as Param3,
       max(Param4) as Param4,
       max(Param5) as Param5
from sample
group by serialnumber
order by InsertDate desc;

Here 就是 SQL Fiddle.

我明白了，OP 确实指定要选择最新的非 NULL 值。

在那种情况下：

select serialnumber, min(InsertDate) as InsertDate,
       max(Param1) keep (dense_rank first order by nvl2(Param1, 1, 2), InsertDate desc) as Param1,
       max(Param2) keep (dense_rank first order by nvl2(Param2, 1, 2), InsertDate desc) as Param2,
       max(Param3) keep (dense_rank first order by nvl2(Param3, 1, 2), InsertDate desc) as Param3,
       max(Param4) keep (dense_rank first order by nvl2(Param4, 1, 2), InsertDate desc) as Param4,
       max(Param5) keep (dense_rank first order by nvl2(Param5, 1, 2), InsertDate desc) as Param5
from sample
group by serialnumber
order by InsertDate desc;

和对应的SQL Fiddle.

Oracle 查询合并按 id 分组并按日期排序的多行

Oracle query for merging multiple rows groupped by id and ordered by date

sql

oracle

group-by

sql-order-by

union-all