SQL - Window Functions with dense_rank() - sql

I have a dataset structured such as the one below stored in Hive, call it df:
+-----+-----+----------+--------+
| id1 | id2 | date | amount |
+-----+-----+----------+--------+
| 1 | 2 | 11-07-17 | 0.93 |
| 2 | 2 | 11-11-17 | 1.94 |
| 2 | 2 | 11-09-17 | 1.90 |
| 1 | 1 | 11-10-17 | 0.33 |
| 2 | 2 | 11-10-17 | 1.93 |
| 1 | 1 | 11-07-17 | 0.25 |
| 1 | 1 | 11-09-17 | 0.33 |
| 1 | 1 | 11-12-17 | 0.33 |
| 2 | 2 | 11-08-17 | 1.90 |
| 1 | 1 | 11-08-17 | 0.30 |
| 2 | 2 | 11-12-17 | 2.01 |
| 1 | 2 | 11-12-17 | 1.00 |
| 1 | 2 | 11-09-17 | 0.94 |
| 2 | 2 | 11-07-17 | 1.94 |
| 1 | 2 | 11-11-17 | 1.92 |
| 1 | 1 | 11-11-17 | 0.33 |
| 1 | 2 | 11-10-17 | 1.92 |
| 1 | 2 | 11-08-17 | 0.94 |
+-----+-----+----------+--------+
I wish to partition by id1 and id2, and then order by date descending within each grouping of id1 and id2, and then rank "amount" within that, where the same "amount" on consecutive days would receive the same rank. The ordered and ranked output I'd hope to see is shown here:
+-----+-----+------------+--------+------+
| id1 | id2 | date | amount | rank |
+-----+-----+------------+--------+------+
| 1 | 1 | 2017-11-12 | 0.33 | 1 |
| 1 | 1 | 2017-11-11 | 0.33 | 1 |
| 1 | 1 | 2017-11-10 | 0.33 | 1 |
| 1 | 1 | 2017-11-09 | 0.33 | 1 |
| 1 | 1 | 2017-11-08 | 0.30 | 2 |
| 1 | 1 | 2017-11-07 | 0.25 | 3 |
| 1 | 2 | 2017-11-12 | 1.00 | 1 |
| 1 | 2 | 2017-11-11 | 1.92 | 2 |
| 1 | 2 | 2017-11-10 | 1.92 | 2 |
| 1 | 2 | 2017-11-09 | 0.94 | 3 |
| 1 | 2 | 2017-11-08 | 0.94 | 3 |
| 1 | 2 | 2017-11-07 | 0.93 | 4 |
| 2 | 2 | 2017-11-12 | 2.01 | 1 |
| 2 | 2 | 2017-11-11 | 1.94 | 2 |
| 2 | 2 | 2017-11-10 | 1.93 | 3 |
| 2 | 2 | 2017-11-09 | 1.90 | 4 |
| 2 | 2 | 2017-11-08 | 1.90 | 4 |
| 2 | 2 | 2017-11-07 | 1.94 | 5 |
+-----+-----+------------+--------+------+
I attempted this with the following SQL query:
SELECT
id1,
id2,
date,
amount,
dense_rank() OVER (PARTITION BY id1, id2 ORDER BY date DESC) AS rank
FROM
df
GROUP BY
id1,
id2,
date,
amount
But that query doesn't seem to be doing what I'd like it to as I'm not receiving the output I'm looking for.
It seems like a window function using dense_rank, partition by and order by is what I need but I can't quite seem to get it to give me that sample output that I desire. Any help would be much appreciated! Thanks!

This is quite tricky. I think you need to use lag() to see where the value changes and then do a cumulative sum:
select df.*,
sum(case when prev_amount = amount then 0 else 1 end) over
(partition by id1, id2 order by date desc) as rank
from (select df.*,
lag(amount) over (partition by id1, id2 order by date desc) as prev_amount
from df
) df;

Related

Postgresql sum not working as expected when it is clear

I am solving the following Hard Leetcode SQL Question.
Link to Question: https://leetcode.com/problems/trips-and-users/
(You can directly look at the solution and understand the problem)
Question:
Trips table:
+----+-----------+-----------+---------+---------------------+------------+
| id | client_id | driver_id | city_id | status | request_at |
+----+-----------+-----------+---------+---------------------+------------+
| 1 | 1 | 10 | 1 | completed | 2013-10-01 |
| 2 | 2 | 11 | 1 | cancelled_by_driver | 2013-10-01 |
| 3 | 3 | 12 | 6 | completed | 2013-10-01 |
| 4 | 4 | 13 | 6 | cancelled_by_client | 2013-10-01 |
| 5 | 1 | 10 | 1 | completed | 2013-10-02 |
| 6 | 2 | 11 | 6 | completed | 2013-10-02 |
| 7 | 3 | 12 | 6 | completed | 2013-10-02 |
| 8 | 2 | 12 | 12 | completed | 2013-10-03 |
| 9 | 3 | 10 | 12 | completed | 2013-10-03 |
| 10 | 4 | 13 | 12 | cancelled_by_driver | 2013-10-03 |
+----+-----------+-----------+---------+---------------------+------------+
Users table:
+----------+--------+--------+
| users_id | banned | role |
+----------+--------+--------+
| 1 | No | client |
| 2 | Yes | client |
| 3 | No | client |
| 4 | No | client |
| 10 | No | driver |
| 11 | No | driver |
| 12 | No | driver |
| 13 | No | driver |
+----------+--------+--------+
Output:
+------------+-------------------+
| Day | Cancellation Rate |
+------------+-------------------+
| 2013-10-01 | 0.33 |
| 2013-10-02 | 0.00 |
| 2013-10-03 | 0.50 |
+------------+-------------------+
Here's my code:
SELECT request_at,
count(*) c,
sum(case when status='cancelled_by_driver' or status='cancelled_by_client' then 1 else 0 end) s,
round(sum(case when status='cancelled_by_client' or status='cancelled_by_client' then 1 else 0 end)/count(*),2) as Cancellation_rate
FROM trips
WHERE
client_id not in (select users_id from users where banned = 'Yes')
AND
driver_id not in (select users_id from users where banned = 'Yes')
GROUP BY request_at;
And the output is:
request_at | c | s | cancellation_rate
------------+---+---+-------------------
2013-10-01 | 3 | 1 | 0.00
2013-10-03 | 2 | 1 | 0.00
2013-10-02 | 2 | 0 | 0.00
How is the cancellation_rate is 0.00 when it is clear by looking at previous columns(s/c) that it should be 0.33,0.50, 0.00.
The good news is you're only off by a typo.
In your example you are using cancelled_by_client or cancelled_by_client
round(sum(case when status='cancelled_by_client' or status='cancelled_by_client' then 1 else 0 end)/count(*),2) as Cancellation_rate
rather than:
.. when status='cancelled_by_driver' or status='cancelled_by_client' then ..
which would return:
request_at
c
s
cancellation_rate
2013-10-01
3
1
0.33
2013-10-02
2
0
0.00
2013-10-03
2
1
0.50

windowing function avg in Hive with - over (order by colName)

i'm trying to understand how windowing function avg works, and somehow it seems to not be working as i expect.
here is the dataset :
select * from winsales;
+-------------------+------------------+--------------------+-------------------+---------------+-----------------------+--+
| winsales.salesid | winsales.dateid | winsales.sellerid | winsales.buyerid | winsales.qty | winsales.qty_shipped |
+-------------------+------------------+--------------------+-------------------+---------------+-----------------------+--+
| 30001 | NULL | 3 | b | 10 | 10 |
| 10001 | NULL | 1 | c | 10 | 10 |
| 10005 | NULL | 1 | a | 30 | NULL |
| 40001 | NULL | 4 | a | 40 | NULL |
| 20001 | NULL | 2 | b | 20 | 20 |
| 40005 | NULL | 4 | a | 10 | 10 |
| 20002 | NULL | 2 | c | 20 | 20 |
| 30003 | NULL | 3 | b | 15 | NULL |
| 30004 | NULL | 3 | b | 20 | NULL |
| 30007 | NULL | 3 | c | 30 | NULL |
| 30001 | NULL | 3 | b | 10 | 10 |
+-------------------+------------------+--------------------+-------------------+---------------+-----------------------+--+
When i fire the following query ->
select salesid, sellerid, qty, avg(qty) over (order by sellerid) as avg_qty from winsales order by sellerid,salesid;
I get the following ->
+----------+-----------+------+---------------------+--+
| salesid | sellerid | qty | avg_qty |
+----------+-----------+------+---------------------+--+
| 10001 | 1 | 10 | 20.0 |
| 10005 | 1 | 30 | 20.0 |
| 20001 | 2 | 20 | 20.0 |
| 20002 | 2 | 20 | 20.0 |
| 30001 | 3 | 10 | 18.333333333333332 |
| 30001 | 3 | 10 | 18.333333333333332 |
| 30003 | 3 | 15 | 18.333333333333332 |
| 30004 | 3 | 20 | 18.333333333333332 |
| 30007 | 3 | 30 | 18.333333333333332 |
| 40001 | 4 | 40 | 19.545454545454547 |
| 40005 | 4 | 10 | 19.545454545454547 |
+----------+-----------+------+---------------------+--+
Question is - how is the avg(qty) being calculated.
Since i'm not using partition by, i would expect the avg(qty) to be the same for all rows.
Any ideas ?
if you want to have same avg(qty) to get for all rows then remove order by sellerid in over clause, then you are going to have 19.545454545454547 value for all the rows.
Query to get same avg(qty) for all rows:
hive> select salesid, sellerid, qty, avg(qty) over () as avg_qty from winsales order by sellerid,salesid;
If we include order by sellerid in over clause then you are getting cumulative avg is caluculated for each sellerid.
i.e. for
sellerid 1 you are having 2 records total 2 records with qty as 10,30 so avg would be
(10+30)/2.
sellerid 2 you are having 2 records total 4 records with qty as 20,20 so avg would be
(10+30+20+20)/4 = 20.0
sellerid 3 you are having 5 records total 9 records with qty as so 10,10,15,20,30 avg would be
(10+30+20+20+10+10+15+20+30)/9 = 18.333
sellerid 4 avg is 19.545454545454547
when we include over clause then this is an expected behavior from hive.

SQL window excluding current group?

I'm trying to provide rolled up summaries of the following data including only the group in question as well as excluding the group. I think this can be done with a window function, but I'm having problems with getting the syntax down (in my case Hive SQL).
I want the following data to be aggregated
+------------+---------+--------+
| date | product | rating |
+------------+---------+--------+
| 2018-01-01 | A | 1 |
| 2018-01-02 | A | 3 |
| 2018-01-20 | A | 4 |
| 2018-01-27 | A | 5 |
| 2018-01-29 | A | 4 |
| 2018-02-01 | A | 5 |
| 2017-01-09 | B | NULL |
| 2017-01-12 | B | 3 |
| 2017-01-15 | B | 4 |
| 2017-01-28 | B | 4 |
| 2017-07-21 | B | 2 |
| 2017-09-21 | B | 5 |
| 2017-09-13 | C | 3 |
| 2017-09-14 | C | 4 |
| 2017-09-15 | C | 5 |
| 2017-09-16 | C | 5 |
| 2018-04-01 | C | 2 |
| 2018-01-13 | D | 1 |
| 2018-01-14 | D | 2 |
| 2018-01-24 | D | 3 |
| 2018-01-31 | D | 4 |
+------------+---------+--------+
Aggregated results:
+------+-------+---------+----+------------+------------------+----------+
| year | month | product | ct | avg_rating | avg_rating_other | other_ct |
+------+-------+---------+----+------------+------------------+----------+
| 2018 | 1 | A | 5 | 3.4 | 2.5 | 4 |
| 2018 | 2 | A | 1 | 5 | NULL | 0 |
| 2017 | 1 | B | 4 | 3.6666667 | NULL | 0 |
| 2017 | 7 | B | 1 | 2 | NULL | 0 |
| 2017 | 9 | B | 1 | 5 | 4.25 | 4 |
| 2017 | 9 | C | 4 | 4.25 | 5 | 1 |
| 2018 | 4 | C | 1 | 2 | NULL | 0 |
| 2018 | 1 | D | 4 | 2.5 | 3.4 | 5 |
+------+-------+---------+----+------------+------------------+----------+
I've also considered producing two aggregates, one with the product in question and one without, but having trouble with creating the appropriate joining key.
You can do:
select year(date), month(date), product,
count(*) as ct, avg(rating) as avg_rating,
sum(count(*)) over (partition by year(date), month(date)) - count(*) as ct_other,
((sum(sum(rating)) over (partition by year(date), month(date)) - sum(rating)) /
(sum(count(*)) over (partition by year(date), month(date)) - count(*))
) as avg_other
from t
group by year(date), month(date), product;
The rating for the "other" is a bit tricky. You need to add everything up and subtract out the current row -- and calculate the average by doing the sum divided by the count.

SQL Getting Running Count with SUM and OVER

In sql I have a history table for each item we have and they can have a record of in or out with a quantity for each action. I'm trying to get a running count of how many of an item we have based on whether it's an activity of out or in. Here is my final sql:
SELECT itemid,
activitydate,
activitycode,
SUM(quantity) AS quantity,
SUM(CASE WHEN activitycode = 'IN'
THEN quantity
WHEN activitycode = 'OUT'
THEN -quantity
ELSE 0 END) OVER (PARTITION BY itemid ORDER BY activitydate rows unbounded preceding) AS runningcount
FROM itemhistory
GROUP BY itemid,
activitydate,
activitycode
This results in:
+--------+-------------------------+--------------+----------+--------------+
| itemid | activitydate | activitycode | quantity | runningcount |
+--------+-------------------------+--------------+----------+--------------+
| 1 | 2017-06-08 13:58:00.000 | IN | 1 | 1 |
| 1 | 2017-06-08 16:02:00.000 | IN | 6 | 2 |
| 1 | 2017-06-15 11:43:00.000 | OUT | 3 | 1 |
| 1 | 2017-06-19 12:36:00.000 | IN | 1 | 2 |
| 2 | 2017-06-08 13:50:00.000 | IN | 5 | 1 |
| 2 | 2017-06-12 12:41:00.000 | IN | 4 | 2 |
| 2 | 2017-06-15 11:38:00.000 | OUT | 2 | 1 |
| 2 | 2017-06-20 12:54:00.000 | IN | 15 | 2 |
| 2 | 2017-06-08 13:52:00.000 | IN | 5 | 3 |
| 2 | 2017-06-12 13:09:00.000 | IN | 1 | 4 |
| 2 | 2017-06-15 11:47:00.000 | OUT | 1 | 3 |
| 2 | 2017-06-20 13:14:00.000 | IN | 1 | 4 |
+--------+-------------------------+--------------+----------+--------------+
I want the end result to look like this:
+--------+-------------------------+--------------+----------+--------------+
| itemid | activitydate | activitycode | quantity | runningcount |
+--------+-------------------------+--------------+----------+--------------+
| 1 | 2017-06-08 13:58:00.000 | IN | 1 | 1 |
| 1 | 2017-06-08 16:02:00.000 | IN | 6 | 7 |
| 1 | 2017-06-15 11:43:00.000 | OUT | 3 | 4 |
| 1 | 2017-06-19 12:36:00.000 | IN | 1 | 5 |
| 2 | 2017-06-08 13:50:00.000 | IN | 5 | 5 |
| 2 | 2017-06-12 12:41:00.000 | IN | 4 | 9 |
| 2 | 2017-06-15 11:38:00.000 | OUT | 2 | 7 |
| 2 | 2017-06-20 12:54:00.000 | IN | 15 | 22 |
| 2 | 2017-06-08 13:52:00.000 | IN | 5 | 27 |
| 2 | 2017-06-12 13:09:00.000 | IN | 1 | 28 |
| 2 | 2017-06-15 11:47:00.000 | OUT | 1 | 27 |
| 2 | 2017-06-20 13:14:00.000 | IN | 1 | 28 |
+--------+-------------------------+--------------+----------+--------------+
You want sum(sum()), because this is an aggregation query:
SELECT itemid, activitydate, activitycode,
SUM(quantity) AS quantity,
SUM(SUM(CASE WHEN activitycode = 'IN' THEN quantity
WHEN activitycode = 'OUT' THEN -quantity
ELSE 0
END)
) OVER (PARTITION BY itemid ORDER BY activitydate ) AS runningcount
FROM itemhistory
GROUP BY itemid, activitydate, activitycode

MDX last non empty over multiple dimensions

I would geatly appreciate if someone could help me with the
problem. I have the following fact table:
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| EntryNo | ItemNo | CompanyId | BranchId | LocationId | ValuationDate | ValuatedQty | ValuatedAmount |
+=========+========+===========+==========+============+===============+=============+================+
| 1 | Item1 | 1 | 1 | 1 | 2016-03-01 | 0 | 0 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 2 | Item1 | 1 | 2 | 1 | 2016-03-01 | 4 | 400 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 3 | Item1 | 1 | 1 | 1 | 2016-03-02 | 10 | 1000 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 4 | Item2 | 1 | 1 | 2 | 2016-03-02 | 4 | 200 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 5 | Item2 | 2 | 2 | 2 | 2016-03-02 | 6 | 300 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 6 | Item1 | 2 | 2 | 1 | 2016-03-03 | 0 | 0 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 7 | Item3 | 1 | 2 | 3 | 2016-03-03 | 0 | 0 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
| 8 | Item1 | 2 | 2 | 3 | 2016-03-03 | 9 | 450 |
+---------+--------+-----------+----------+------------+---------------+-------------+----------------+
There are two measures that represent "overstocked" items on a particular day.
Is it possible to create a calculated member that will allow for slicing data
on the all linked dimensions (Items, Companies, etc.) ? I guess the LastNonEmpty agregration
would be useful here except it is not available in the standard edition.
Given the example the results should be as follows:
By Company:
+---------+-------------+----------------+
| Company | ValuatedQty | ValuatedAmount |
+=========+=============+================+
| 1 | 14 | 1200 |
+---------+-------------+----------------+
| 2 | 15 | 750 |
+---------+-------------+----------------+
By Date:
+------------+-------------+----------------+
| Date | ValuatedQty | ValuatedAmount |
+============+=============+================+
| 2016-03-01 | 4 | 400 |
+------------+-------------+----------------+
| 2016-03-02 | 16 | 1300 |
+------------+-------------+----------------+
| 2016-03-03 | 9 | 450 |
+------------+-------------+----------------+
By Item:
+-------+-------------+----------------+
| Item | ValuatedQty | ValuatedAmount |
+=======+=============+================+
| Item1 | 9 | 450 |
+-------+-------------+----------------+
| Item2 | 6 | 300 |
+-------+-------------+----------------+
| Item3 | 0 | 0 |
+-------+-------------+----------------+
Two functions that come to mind for your requirements are:
Tail: https://msdn.microsoft.com/en-us/library/ms146056.aspx
Bottomcount: https://msdn.microsoft.com/en-us/library/ms144864.aspx
So with Tail something like the following is possible:
WITH SET [LastYearPerSubCat] AS
GENERATE(
[Product].[Product Categories].[SubCategory].members AS S,
S.CURRENTMEMBER
*
TAIL(
NONEMPTY(
[Date].[Calendar Year].[Calendar Year].MEMBERS,
S.CURRENTMEMBER
)
)
)
SELECT
[Measures].[Reseller Gross Profit] ON 0
,[LastYearPerSubCat] ON 1
FROM [Adventure Works];