Athena 获取每组中的最小值和对应的其他列值

Question

输入表

user id action  date           collection

aaa  1   view   2020-09-01     {some JSON data_1}
aaa  1   view   2020-09-02     {some JSON data_2}
aaa  1   view   2020-09-03     {some JSON data_3}
bbb  2   view   2020-09-08     {some JSON data_22}
bbb  2   view   2020-09-09     {some JSON data_23}
ccc  2   view   2020-09-01     {some JSON data_99}
ddd  3   view   2020-09-01     {some JSON data_88}

输出表

user id action  date           collection

aaa  1   view   2020-09-01     {some JSON data_1}
bbb  2   view   2020-09-08     {some JSON data_22}
ccc  2   view   2020-09-01     {some JSON data_99}
ddd  3   view   2020-09-01     {some JSON data_88}

如果我们看到输入表和输出表，

我想要类似的

group by (user,id,action) then i need min(date) and corresponding collection value

任何人都可以提出一个想法吗？

Answer 1

一种选择是使用子查询进行过滤：

select t.*
from mytable t
where t.date = (
    select min(t1.date) from mytable t1 where t1.user = t.user
)

另一种解决方案是使用窗口函数按date具有相同user的记录进行排名，然后使用该信息过滤结果集：

select *
from (
    select t.*, row_number() over(partition by user order by date) rn
    from mytable t
) t
where rn = 1