table:
| id | action | project_id | created_on | last_updated_on | 
|---|---|---|---|---|
| 1 | Update | 123 | 2021.1.1 | 2021.5.3 | 
| 2 | creation | 123 | 2021.1.4 | 2021.5.2 | 
| 3 | Update | 123 | 2021.1.3 | 2021.5.1 | 
| 4 | Update | 456 | 2021.2.1 | 2021.6.3 | 
| 5 | Update | 456 | 2021.2.2 | 2021.6.2 | 
| 6 | creation | 456 | 2021.2.3 | 2021.6.1 | 
I would like to get a map of project and its most recently created Update action’s last_updated_on.
My statement is
select project_id, last_updated_on from table where action = "Update" group by project_id order by created_on desc limit 1
But I got the error of SELECT list is not in GROUP BY clause and contains nonaggregated column.
I cannot change the ONLY_FULL_GROUP_BY atrribute.
And in my use case I think I cannot add last_updated_on into the group by either.
I also tried
select 
    project_id, 
    (select last_updated_on where created_on = max(created_on)) as "last_updated_on"
    .
    .
    .
but the error still occurred.
Hope someone can help me. Tnanks in advance!
Update:
Desired result of the example table:
| project_id | last_updated_on | 
|---|---|
| 123 | 2021.5.1 | 
| 456 | 2021.6.2 | 
Explanation:
- For project_id = 123, row 1 and 3’sactionareupdate,
- after order by created_on desc limit 1, row 3 is selected, whoselast_updated_onis2021.5.1.
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Answer
You can do:
select project_id, last_updated_on
from (
  select *, row_number() over(partition by project_id 
                              order by last_updated_on desc) as rn
  from t
  where action = 'Update'
) x
where rn = 1
order by created_on
Will show the last Update action for each project. Projects with no Update action at all won’t show up.