我在PostgreSQL中有一个数据帧,如下所示,我想要每个id的最新记录,如果每个id的任何最新记录在任何列中包含NULL值,我想用同一列中的下一个最新值替换它
数据
id ingdt code gender address
1 27-10-2018 NULL NULL street1
1 24-10-2018 1234 NULL street2
1 20-08-2017 3245 M street2
2 24-09-2018 NULL F Astreet
2 24-10-2018 2857 F Bstreet
3 24-08-2018 3489 M NULL
3 22-08-2018 5802 M Cstreet
预期输出
最终输出
id ingdt code gender address
1 27-10-2018 1234 M street1
2 24-10-2018 2857 F Bstreet
3 24-08-2018 3489 M Cstreet
尝试
insert into final_output select * from (
(select code, id from data where code != null order by ingdt limit 1) x join
(select gender, id from data where gender != null order by ingdt limit 1) y join
(select address, id from data where address != null order by ingdt limit 1)z on y.id=x.id)
demo:db<>小提琴
使用窗口功能可以帮助您:
SELECT DISTINCT
id,
max(ingdt) OVER (PARTITION BY id),
first_value(code) OVER (PARTITION BY id ORDER BY code IS NULL, ingdt DESC) AS code,
first_value(gender) OVER (PARTITION BY id ORDER BY gender IS NULL, ingdt DESC) AS gender,
first_value(address) OVER (PARTITION BY id ORDER BY address IS NULL, ingdt DESC) AS address
FROM mytable
ORDER BY id
解释first_value(...) OVER (...)
:
窗口函数可以将行分组到单独的框架中。这是通过关键字PARTITION BY
来完成的。在这种情况下,我为每个id
生成帧。
现在我正在检查列的值是否为NULL
。这给了我true
或false
。我对这个结果进行排序,就像任何先有false
(意思是NOT NULL
(的boolean
列一样。如果有许多NOT NULL
行,则取最近的一行(ingdt DESC
(。这种订购也分别针对每个单独的框架进行。
CCD_ 12计算有序帧的第一个值。