Selecting rows that doesn't have duplicates - sql

Let's say I have the following table:
| sku | id | value | count |
|-----|----|-------|-------|
| A | 1 | 1 | 2 |
| A | 1 | 2 | 2 |
| A | 3 | 3 | 3 |
I want to select rows that don't have the same count for the same id. So my desired outcome is:
| sku | id | value | count |
|-----|----|-------|-------|
| A | 3 | 3 | 3 |
I need something that works with Postgres 10

A simple method is window functions:
select t.*
from (select t.*, count(*) over (partition by sku, id) as cnt
from t
) t
where cnt = 1;
This assumes you really mean the sku/id combination.

Related

SQL Select until Quantity Met

i need a sql query that can show something like this :
My Data :
| id | Purchase Number | Qty |
|:---- |:------:| -----:|
| 1 | A | 3 |
| 2 | B | 2 |
| 3 | C | 4 |
For example i need to take 6 Qty
I want the result will be like this :
| id | Purchase Number | Qty |
|:---- |:------:| -----:|
| 1 | A | 3 |
| 2 | B | 2 |
| 3 | C | 1|
I've read similar thread but cant find what i need
You can use a cumulative sum:
select id, purchase_number,
(case when running_qty < 6 then qty
else 6 - (running_qty - qty)
end)
from (select t.*,
sum(qty) over (order by id) as running_qty
from t
) t
where running_qty - qty < 6;
Here is a db<>fiddle (which uses Postgres but this is standard SQL).

SQL group by changing column

Suppose I have a table sorted by date as so:
+-------------+--------+
| DATE | VALUE |
+-------------+--------+
| 01-09-2020 | 5 |
| 01-15-2020 | 5 |
| 01-17-2020 | 5 |
| 02-03-2020 | 8 |
| 02-13-2020 | 8 |
| 02-20-2020 | 8 |
| 02-23-2020 | 5 |
| 02-25-2020 | 5 |
| 02-28-2020 | 3 |
| 03-13-2020 | 3 |
| 03-18-2020 | 3 |
+-------------+--------+
I want to group by changes in value within that given date range, and add a value that increments each time as an added column to denote that.
I have tried a number of different things, such as using the lag function:
SELECT value, value - lag(value) over (order by date) as count
GROUP BY value
In short, I want to take the table above and have it look like:
+-------------+--------+-------+
| DATE | VALUE | COUNT |
+-------------+--------+-------+
| 01-09-2020 | 5 | 1 |
| 01-15-2020 | 5 | 1 |
| 01-17-2020 | 5 | 1 |
| 02-03-2020 | 8 | 2 |
| 02-13-2020 | 8 | 2 |
| 02-20-2020 | 8 | 2 |
| 02-23-2020 | 5 | 3 |
| 02-25-2020 | 5 | 3 |
| 02-28-2020 | 3 | 4 |
| 03-13-2020 | 3 | 4 |
| 03-18-2020 | 3 | 4 |
+-------------+--------+-------+
I want to eventually have it all in one small table with the earliest date for each.
+-------------+--------+-------+
| DATE | VALUE | COUNT |
+-------------+--------+-------+
| 01-09-2020 | 5 | 1 |
| 02-03-2020 | 8 | 2 |
| 02-23-2020 | 5 | 3 |
| 02-28-2020 | 3 | 4 |
+-------------+--------+-------+
Any help would be very appreciated
you can use a combination of Row_number and Dense_rank functions to get the required results like below:
;with cte
as
(
select t.DATE,t.VALUE
,Dense_rank() over(partition by t.VALUE order by t.DATE) as d_rank
,Row_number() over(partition by t.VALUE order by t.DATE) as r_num
from table t
)
Select t.Date,t.Value,d_rank as count
from cte
where r_num = 1
You can use a lag and cumulative sum and a subquery:
SELECT value,
SUM(CASE WHEN prev_value = value THEN 0 ELSE 1 END) OVER (ORDER BY date)
FROM (SELECT t.*, LAG(value) OVER (ORDER BY date) as prev_value
FROM t
) t
Here is a db<>fiddle.
You can recursively use lag() and then row_number() analytic functions :
WITH t2 AS
(
SELECT LAG(value,1,value-1) OVER (ORDER BY date) as lg,
t.*
FROM t
)
SELECT t2.date,t2.value, ROW_NUMBER() OVER (ORDER BY t2.date) as count
FROM t2
WHERE value - lg != 0
Demo
and filter through inequalities among the returned values from those functions.

Count rows in table that are the same in a sequence

I have a table that looks like this
+----+------------+------+
| ID | Session_ID | Type |
+----+------------+------+
| 1 | 1 | 2 |
| 2 | 1 | 4 |
| 3 | 1 | 2 |
| 4 | 2 | 2 |
| 5 | 2 | 2 |
| 6 | 3 | 2 |
| 7 | 3 | 1 |
+----+------------+------+
And I would like to count all occurences of a type that are in a sequence.
Output look some how like this:
+------------+------+-----+
| Session_ID | Type | cnt |
+------------+------+-----+
| 1 | 2 | 1 |
| 1 | 4 | 1 |
| 1 | 2 | 1 |
| 2 | 2 | 2 |
| 3 | 2 | 1 |
| 3 | 1 | 1 |
+------------+------+-----+
A simple group by like
SELECT session_id, type, COUNT(type)
FROM table
GROUP BY session_id, type
doesn't work, since I need to group only rows that are "touching".
Is this possible with a merge sql-select or will I need some sort of coding. Stored Procedure or Application side coding?
UPDATE Sequence:
If the following row has the same type, it should be counted (ordered by ID).
to determine the sequence the ID is the key with the session_ID, since I just want to group rows with the same session_ID.
So if there are 3 rows is in one session
row with the ID 1 has type 1,
and the second row has type 1
and row 3 has type 2
Input:
+----+------------+------+
| ID | Session_ID | Type |
+----+------------+------+
| 1 | 1 | 1 |
| 2 | 1 | 1 |
| 3 | 1 | 2 |
+----+------------+------+
The squence is Row 1 to Row 2. This three row should output
Output:
+------------+------+-------+
| Session_ID | Type | count |
+------------+------+-------+
| 1 | 1 | 2 |
| 3 | 2 | 1 |
+------------+------+-------+
You can use a difference of id and row_number() to identify the gaps and then perform your count
;with cte as
(
Select *, id - row_number() over (partition by session_id,type order by id) as grp
from table
)
select session_id,type,count(*) as cnt
from cte
group by session_id,type,grp
order by max(id)

SQL Query - is there a way to ascending id number which has same value?

I want to know if there is a way to repeating ascending if id number has a same value??
the details :
let say I have a value of id like this:
|-----|
| id |
|-----|
| 1 |
| 1 |
| 2 |
| 3 |
| 3 |
| 4 |
| 5 |
| 2 |
| 4 |
| 5 |
|-----|
then I want to ascending that id like this :
|-----|
| id |
|-----|
| 1 |
| 2 |
| 3 |
| 4 |
| 5 |
| 1 |
| 2 |
| 3 |
| 4 |
| 5 |
|-----|
I don't know how to say that, also don't know the keyword to find it on google, so I hope my question is usefull for everyone in case had a same issue.
In ANSI standard SQL, you can use row_number() for this purpose:
select id
from (select t.*, row_number() over (partition by id order by id) as seqnum
from t
) t
order by seqnum, id;
To be honest, the subquery is not necessary, so you can do:
select id
from t
order by row_number() over (partition by id order by id), id;

group by top two results based on order

I have been trying to get this to work with some row_number, group by, top, sort of things, but I am missing some fundamental concept. I have a table like so:
+-------+-------+-------+
| name | ord | f_id |
+-------+-------+-------+
| a | 1 | 2 |
| b | 5 | 2 |
| c | 6 | 2 |
| d | 2 | 1 |
| e | 4 | 1 |
| a | 2 | 3 |
| c | 50 | 4 |
+-------+-------+-------+
And my desired output would be:
+-------+---------+--------+-------+
| f_id | ord_n | ord | name |
+-------+---------+--------+-------+
| 2 | 1 | 1 | a |
| 2 | 2 | 5 | b |
| 1 | 1 | 2 | d |
| 1 | 2 | 4 | e |
| 3 | 1 | 2 | a |
| 4 | 1 | 50 | c |
+-------+---------+--------+-------+
Where data is ordered by the ord value, and only up to two results per f_id. Should I be working on a Stored Procedure for this or can I just do it with SQL? I have experimented with some select TOP subqueries, but nothing has even come close..
Here are some statements to create the test table:
create table help(name varchar(255),ord tinyint,f_id tinyint);
insert into help values
('a',1,2),
('b',5,2),
('c',6,2),
('d',2,1),
('e',4,1),
('a',2,3),
('c',50,4);
You may use Rank or DENSE_RANK functions.
select A.name, A.ord_n, A.ord , A.f_id from
(
select
RANK() OVER (partition by f_id ORDER BY ord asc) AS "Rank",
ROW_NUMBER() OVER (partition by f_id ORDER BY ord asc) AS "ord_n",
help.*
from help
) A where A.rank <= 2
Sqlfiddle demo