I need to query a table with 3 rows: id, ip and user_id
I want to return only the rows that have unique values of ip and user_id (not itself unique, but unique as a pair) eg:
id ip user_id
--------------------------------
1 1 2
2 1 2
3 1 2
4 2 5
5 2 5
6 2 8
7 2 8
8 3 10
9 3 11
the result must be:
id ip
------------
1 1
4 2
2 8
6 2
8 3
9 3
I'm using Oracle database.
select min(id),ip from table
group by ip,user_id
select id, ip
from the_table
join (
select min(id) as min_id
from the_table
group by ip, user_id
) t on t.min_id = the_table.id
order by id;
or:
select id, ip
from (
select id,
ip,
row_number() over (partition by ip_user_id order by id) as rn
from the_table
) t
where rn = 1
order by id;
Related
With subquery I need to select after first five rows for each group of id_student and must common values of id_desireCollage between id_student.
More explain : select common collages for each student desires after his five chosen desires
ID
id_desireCollage
id_student
1
1
1
2
2
1
3
3
1
4
4
1
5
5
1
6
8
1
7
9
1
8
7
1
9
2
2
10
12
2
11
1
2
12
3
2
13
6
2
14
5
2
15
8
2
16
9
2
17
7
2
18
4
3
19
3
3
20
2
3
21
1
3
22
8
3
23
9
3
24
7
3
25
5
3
Something like
select id_desireCollage
from
(select *
from desires ds
where ds.id_desireCollage = desires.id_desireCollage)
group by (id_student)
having count(*) > 5
Expected result is:
id_desireCollage
7
9
Try the following:
select id_desireCollage
from
(
select d.*,
row_number() over (partition by id_student order by ID) as rn
from desires d
) T
where rn > 5
group by id_desireCollage
order by count(*) desc
fetch first 1 row with ties
If you don't want to use the row number function (as you commented), you may try the following - supposing there are no gaps in the ID column:
select id_desireCollage
from desires d
where id >=
(
select min(id)+5
from desires t
where t.id_student = d.id_student
)
group by id_desireCollage
order by count(*) desc
fetch first 1 row with ties
See demo
As suggested by #MatBailie, if you meant by common, that all students have selected the id_desireCollage value then you could use the following:
select id_desireCollage
from desires d
where id >=
(
select min(id)+5
from desires t
where t.id_student = d.id_student
)
group by id_desireCollage
having count(*)=
(
select count(distinct id_student)
from desires
)
I am having some trouble with the below query. I do understand I need to group by ID and Category, but I only want to group by ID while keeping the rest of the columns based on Rank being max. Is there a way to only group by certain columns?
select ID, Category, max(rank)
from schema.table1
group by ID
Input:
ID Category Rank
111 3 4
111 1 5
123 5 3
124 7 2
Current Output
ID Category Rank
111 3 4
111 9 1
123 5 3
124 7 2
Desired Output
ID Category Rank
111 1 5
123 5 3
124 7 2
You can use:
select *
from table1
where (id, rank) in (select id, max(rank) from table1 group by id)
Result:
ID CATEGORY RANK
---- --------- ----
111 1 5
123 5 3
124 7 2
Or you can use the ROW_NUMBER() window function. For example:
select *
from (
select *,
row_number() over(partition by id order by rank desc) as rn
from table1
) x
where rn = 1
See running example at db<>fiddle.
You can try using - row_number()
select * from
(
select ID, Category,rank, row_number() over(partition by id order by rank desc) as rn
from schema.table1
)A where rn=1
For example, N is 10 and a table looks like
id
1
2
3
4
5
6
7
10
11
12
13
108
109
111
112
113
Need to find first N rows that have unique value with mod(id, N).
Expected result is
mod10
1
2
3
4
5
6
7
10
108
109
I've tried something like
select *
from
(
select id, id % 10 as seq_id
from accounts order by id
) as s1
group by s1.seq_id limit 10;`
but not working.
You can use window function here -
SELECT id
FROM (SELECT id, ROW_NUMBER() OVER(PARTITION BY id % 10 ORDER BY id) RN
FROM table_name
) X
WHERE RN = 1
ORDER BY id
You can try the below one - using row_number()
DEMO
with cte as
(
select id, row_number() over(partition by seq_id order by id) as rn
from
(
select id, id % 10 as seq_id from tablename
)A
)
select id from cte where rn=1 order by id
OUTPUT:
id
1
2
3
4
5
6
7
10
108
109
I am trying to figure out how to select up to lets say 2 results per key that I have in my table.
My table looks like the following
uid map
1 11
1 12
1 16
1 21
1 26
2 1
2 11
2 14
2 12
2 22
3 12
3 15
3 16
What Im looking to do is select up to 2 rows of data for each uid
example results:
uid map
1 11
1 12
2 1
2 11
3 12
3 15
Thanks for any help you can provide!
Using ANSI-standard SQL, the simplest way is row_number():
select uid, map
from (select t.*, row_number() over (partition by uid order by map) as seqnum
from t
) t
where seqnum <= 2;
SELECT *
FROM table1 a
WHERE
(
SELECT COUNT(*)
FROM table1 b
WHERE a.uid = b.uid AND
a.map <= b.map
) <= 2
Here's part of my table:
id team_id log_id
1 12 1
2 12 1
3 12 1
4 12 1
5 1 2
6 1 2
7 1 3
8 1 3
What query would produce this output (so only the records with the highest log_id values are returned that correspond to team_id)?
id team_id log_id
1 12 1
2 12 1
3 12 1
4 12 1
7 1 3
8 1 3
SELECT *
FROM mytable t
WHERE log_id = (SELECT MAX(log_id) FROM mytable WHERE team_id = t.team_id)
SELECT id, team_id, log_id
FROM table1 t2
JOIN (SELECT team_id, MAX(log_id) max_log_id
FROM table1
GROUP BY team_id) t2 ON t1.team_id = t2.team_id
AND t1.log_id = t2.max_log_id