Retrieve max date for distinct IDs in a table [duplicate] - sql

Question

This question already has answers here:
Fetch the rows which have the Max value for a column for each distinct value of another column
(35 answers)
GROUP BY with MAX(DATE) [duplicate]
(6 answers)
Select First Row of Every Group in sql [duplicate]
(2 answers)
Oracle SQL query: Retrieve latest values per group based on time [duplicate]
(2 answers)
Return row with the max value of one column per group [duplicate]
(3 answers)
Closed 3 years ago.
I have the table ABC with the following data
Id Name Date Execution id
-- ---- --------- -------------
1 AA 09SEP2019 11
1 AA 08SEP2019 22
1 AA 07SEP2019 33
2 BB 09SEP2019 44
2 BB 08SEP2019 55
2 BB 07SEP2019 66
And I want to get for every distinct ID in the table its max date. So the result set must be as the following
Id Name Date Execution id
-- ---- --------- -------------
1 AA 09SEP2019 11
2 BB 09SEP2019 44
The query that returns the result I need
WITH MaxDate as (
SELECT Id,Name,Max(Date) from ABC group by Id,Name
)
SELECT view1.*, view2.exection_id
from
MaxDate view1,
ABC view2
WHERE
view1.date=view2.date and
view1.name=view2.name;
I don't like to get the max date for the distinct ID by this way. May be there is another way ? Might be there is more easiest way?

Answer 1

One way is to use RANK:
WITH cte AS (
SELECT ABC.*, RANK() OVER(PARTITION BY Id,Name ORDER BY Date DESC) rnk
FROM ABC
)
SELECT *
FROM cte
WHERE rnk = 1
ORDER BY id;

Answer 2

You can use keep dense_rank last do to this in one level of query, as long as you only want one or a small number of column retained:
select id,
name,
max(date_) as date_,
max(execution_id) keep (dense_rank last order by date_) as execution_id
from abc
group by id, name
order by id;
ID NAME DATE_ EXECUTION_ID
---------- ---- ---------- ------------
1 AA 2019-09-09 11
2 BB 2019-09-09 44
If ID and name are not always the same, and you want the name form the latest date too, then use the same pattern:
select id,
max(name) keep (dense_rank last order by date_) as name,
max(date_) as date_,
max(execution_id) keep (dense_rank last order by date_) as execution_id
from abc
group by id
order by id;
which gets the same result with your sample data.
With lots of columns it's probably simpler to use a subquery (CTE or inline view) with a ranking function and a filter (as #Lukasz shows).

Answer 3

With NOT EXISTS:
select t.* from ABC t
where not exists (
select 1 from ABC
where "Id" = t."Id" and "Name" = t."Name" and "Date" > t."Date"
)
I used and name = t.name only because you have it in your code.
If it is not needed you can remove it.
See the demo.
Results:
Id | Name | Date | Execution id
-: | :--- | :---------| -----------:
1 | AA | 09-SEP-19 | 11
2 | BB | 09-SEP-19 | 44