Selecting maximun value in postgresql table when maximum values are not distinct - postgresql

I have a table coltures_report with fields application_id, coltures_id and row_step. I would like to get the maximum value for row_step grouped by a combination of application_id and coltures_id. However row_step can have not unique values and I would to get all the rows with the maximum values.
id | application_id| coltures_id | row_step |
----+---------------+-------------+----------+
1 | 1169 | 4 | 5 |
2 | 1169 | 5 | 5 |
3 | 1169 | 2 | 0 |
4 | 1124 | 1 | 5 |
5 | 1124 | 1 | 4 |
6 | 1156 | 1 | 5 |
7 | 1156 | 2 | 5 |
8 | 1156 | 3 | 5 |
Expected result is
id | application_id| coltures_id | row_step |
----+---------------+-------------+----------+
1 | 1169 | 4 | 5 |
2 | 1169 | 5 | 5 |
3 | 1124 | 1 | 5 |
4 | 1156 | 1 | 5 |
5 | 1156 | 2 | 5 |
6 | 1156 | 3 | 5 |


With NOT EXISTS:
select cr.* from coltures_report cr
where not exists (
select 1 from coltures_report
where application_id = cr.application_id and row_step > cr.row_step
)
or with rank() window function:
select cr.id, cr.application_id, cr.coltures_id, cr.row_step
from (
select *,
rank() over (partition by application_id order by row_step desc) rn
from coltures_report
) cr
where cr.rn = 1
Or with a correlated subquery:
select cr.* from coltures_report cr
where cr.row_step = (select max(row_step) from coltures_report where application_id = cr.application_id)
See the demo.
Results:
> id | application_id | coltures_id | row_step
> -: | -------------: | ----------: | -------:
> 1 | 1169 | 4 | 5
> 2 | 1169 | 5 | 5
> 4 | 1124 | 1 | 5
> 6 | 1156 | 1 | 5
> 7 | 1156 | 2 | 5
> 8 | 1156 | 3 | 5

Related

partition by for iterval of 2 seconds

I have a DB with a field of timestamp,
I want to partition it for every 2 seconds (I know how to do it for 1 minute and one second)
this is an example of the DB:
create table data_t(id integer, time_t timestamp without time zone, data_t integer );
insert into data_t(id,time_t,data_t) values(1,'1999-01-08 04:05:06',248),
(2,'1999-01-08 04:05:06.03',45),
(3,'1999-01-08 04:05:06.035',98),
(4,'1999-01-08 04:05:06.9',57),
(5,'1999-01-08 04:05:07',86),
(6,'1999-01-08 04:05:08',84),
(7,'1999-01-08 04:05:08.5',832),
(8,'1999-01-08 04:05:08.7',86),
(9,'1999-01-08 04:05:08.9',863),
(10,'1999-01-08 04:05:9',866),
(11,'1999-01-08 04:05:10',862),
(12,'1999-01-08 04:05:10.5',863),
(13,'1999-01-08 04:05:10.55',826),
(14,'1999-01-08 04:05:11',816),
(15,'1999-01-08 04:05:11.7',186),
(16,'1999-01-08 04:05:12',862),
(17,'1999-01-08 04:05:12.5',826)
;
with t as (
select id,
time_t,
date_trunc('second', data_t.time_t) as time_t_1,
data_t
from data_t
), t1 as(
select *,
extract(hour from time_t_1) as h,
extract(minute from time_t_1) as m,
extract(second from time_t_1) as s
from t ) select *,
row_number() over(partition by h,m,s order by time_t_1) as t_sequence
from t1;
the output of this is:
| id | time_t | time_t_1 | data_t | h | m | s | t_sequence |
|----|--------------------------|----------------------|--------|---|---|----|------------|
| 1 | 1999-01-08T04:05:06Z | 1999-01-08T04:05:06Z | 248 | 4 | 5 | 6 | 1 |
| 2 | 1999-01-08T04:05:06.03Z | 1999-01-08T04:05:06Z | 45 | 4 | 5 | 6 | 2 |
| 3 | 1999-01-08T04:05:06.035Z | 1999-01-08T04:05:06Z | 98 | 4 | 5 | 6 | 3 |
| 4 | 1999-01-08T04:05:06.9Z | 1999-01-08T04:05:06Z | 57 | 4 | 5 | 6 | 4 |
| 5 | 1999-01-08T04:05:07Z | 1999-01-08T04:05:07Z | 86 | 4 | 5 | 7 | 1 |
| 6 | 1999-01-08T04:05:08Z | 1999-01-08T04:05:08Z | 84 | 4 | 5 | 8 | 1 |
| 7 | 1999-01-08T04:05:08.5Z | 1999-01-08T04:05:08Z | 832 | 4 | 5 | 8 | 2 |
| 8 | 1999-01-08T04:05:08.7Z | 1999-01-08T04:05:08Z | 86 | 4 | 5 | 8 | 3 |
| 9 | 1999-01-08T04:05:08.9Z | 1999-01-08T04:05:08Z | 863 | 4 | 5 | 8 | 4 |
| 10 | 1999-01-08T04:05:09Z | 1999-01-08T04:05:09Z | 866 | 4 | 5 | 9 | 1 |
| 11 | 1999-01-08T04:05:10Z | 1999-01-08T04:05:10Z | 862 | 4 | 5 | 10 | 1 |
| 12 | 1999-01-08T04:05:10.5Z | 1999-01-08T04:05:10Z | 863 | 4 | 5 | 10 | 2 |
| 13 | 1999-01-08T04:05:10.55Z | 1999-01-08T04:05:10Z | 826 | 4 | 5 | 10 | 3 |
| 14 | 1999-01-08T04:05:11Z | 1999-01-08T04:05:11Z | 816 | 4 | 5 | 11 | 1 |
| 15 | 1999-01-08T04:05:11.7Z | 1999-01-08T04:05:11Z | 186 | 4 | 5 | 11 | 2 |
| 16 | 1999-01-08T04:05:12Z | 1999-01-08T04:05:12Z | 862 | 4 | 5 | 12 | 1 |
| 17 | 1999-01-08T04:05:12.5Z | 1999-01-08T04:05:12Z | 826 | 4 | 5 | 12 | 2 |
as you can see the t_sequence start over every second but I want it to start over every 2 seconds,
is there a way to do it?
link for SQL fiddle with all the data

PostgreSQL limit by group, only show first 2 store options

I need to select first 2 lines where the store_name is different than one given for a given product
id | store_name | prod_name
----+------------+------
1 | 1 | A
2 | 1 | B
3 | 1 | C
4 | 1 | A
5 | 2 | E
6 | 2 | A
7 | 3 | G
8 | 2 | A
9 | 1 | A
10 | 3 | A
(10 rows)
result should be store_name <> 3 AND prod_name ='A'
id | store_name | prod_name
----+------------+------
1 | 1 | A
4 | 1 | A
6 | 2 | A
8 | 2 | A

Use the row_number() window function to accomplish this.
Query #1
with first_two as (
select *,
row_number() over (partition by store_name
order by id) as rn
from store_product
where store_name <> 3
and prod_name = 'A'
)
select id, store_name, prod_name
from first_two
where rn <= 2;
| id | store_name | prod_name |
| --- | ---------- | --------- |
| 1 | 1 | A |
| 4 | 1 | A |
| 6 | 2 | A |
| 8 | 2 | A |
View on DB Fiddle

count continuously postgresql data

i need help with counting some data
this what i want
| user_id | action_id | count |
-------------------------------------
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 2 | 2 |
| 4 | 3 | 1 |
| 5 | 3 | 2 |
| 6 | 3 | 3 |
| 7 | 4 | 1 |
| 8 | 5 | 1 |
| 9 | 5 | 2 |
| 10 | 6 | 1 |
this is what i have
| user_id | action_id | count |
-------------------------------
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 2 | 1 |
| 4 | 3 | 1 |
| 5 | 3 | 1 |
| 6 | 3 | 1 |
| 7 | 4 | 1 |
| 8 | 5 | 1 |
| 9 | 5 | 1 |
| 10 | 6 | 1 |
i really need it for create some research about second action from users
how do i do it?
thank you

Using ROW_NUMBER should work here:
SELECT
user_id,
action_id,
ROW_NUMBER() OVER (PARTITION BY action_id ORDER BY user_id) count
FROM yourTable
ORDER BY
user_id;
Demo

Populate zero values in column with next value greater than zero

I have the following Postres code:
SELECT
a.assessmentid,
b.groupid
FROM wo_assessment a
LEFT JOIN wo_group_info b ON a.assessmentid = b.assessmentid
WHERE a.workorderid=2
ORDER BY a.assessmentid
Which returns the following results:
|-------------------|------------|
| assessmentid | groupid |
|-------------------|------------|
| 5 | 5 |
|-------------------|------------|
| 6 | 4 |
|-------------------|------------|
| 7 | 0 |
|-------------------|------------|
| 8 | 5 |
|-------------------|------------|
| 9 | 0 |
|-------------------|------------|
| 10 | 0 |
|-------------------|------------|
I would like to populate the 0 values in the groupid field with the next number above in that column, that isn't 0.
So for example I want my table to look like this:
|-------------------|------------|
| assessmentid | groupid |
|-------------------|------------|
| 5 | 5 |
|-------------------|------------|
| 6 | 4 |
|-------------------|------------|
| 7 | 4 |
|-------------------|------------|
| 8 | 5 |
|-------------------|------------|
| 9 | 5 |
|-------------------|------------|
| 10 | 5 |
|-------------------|------------|

Here is what worked for me:
SELECT q.assessmentid,
first_value(b.groupid ) over (partition by value_partition order by q.assessmentid) FROM (
SELECT a.assessmentid,
b.groupid ,
sum(case when b.groupid is null then 0 else 1 end) over (order by a.assessmentid) as value_partition
FROM wo_assessment as a
LEFT JOIN wo_group_info b ON a.assessmentid = b.assessmentid
ORDER BY a.assessmentid ) as q
LEFT JOIN wo_group_info b ON q.assessmentid = b.assessmentid

Select rows by one column value should only be repeat N times

My table is:
id sub_id datetime resource
---|-----|------------|-------
1 | 10 | 04/03/2009 | 399
2 | 11 | 04/03/2009 | 244
3 | 10 | 04/03/2009 | 555
4 | 10 | 03/03/2009 | 300
5 | 11 | 03/03/2009 | 200
6 | 11 | 03/03/2009 | 500
7 | 11 | 24/12/2008 | 600
8 | 13 | 01/01/2009 | 750
9 | 10 | 01/01/2009 | 760
10 | 13 | 01/01/2009 | 570
11 | 11 | 01/01/2009 | 870
12 | 13 | 01/01/2009 | 670
13 | 13 | 01/01/2009 | 703
14 | 13 | 01/01/2009 | 705
I need to select for each sub_id only 2 times
Result would be:
id sub_id datetime resource
---|-----|------------|-------
1 | 10 | 04/03/2009 | 399
3 | 10 | 04/03/2009 | 555
5 | 11 | 03/03/2009 | 200
6 | 11 | 03/03/2009 | 500
8 | 13 | 01/01/2009 | 750
10 | 13 | 01/01/2009 | 570
How can I achieve this result in postgres ?

Use the window function row_number():
select id, sub_id, datetime, resource
from (
select *, row_number() over (partition by sub_id order by id)
from my_table
) s
where row_number < 3;

look at the order column (I use id to match your sample):
t=# with data as (select *,count(1) over (partition by sub_id order by id) from t)
select id,sub_id,datetime,resource from data where count <3;
id | sub_id | datetime | resource
----+--------+------------+----------
1 | 10 | 2009-03-04 | 399
3 | 10 | 2009-03-04 | 555
2 | 11 | 2009-03-04 | 244
5 | 11 | 2009-03-03 | 200
8 | 13 | 2009-01-01 | 750
10 | 13 | 2009-01-01 | 570
(6 rows)