T-SQL Comparison of Min and Max Values Over Time - sql

Question

Working in SQL Server, I have a table with 4 columns
AccountId
AccountName
SubscriptionAmt
DateKey
It lists each company's SubscriptionAmt by month (DateKey, i.e 201801) as they change over time.
I want to write one select statement including
AccountId, AccountName, EarliestSubscriptionAmt, LatestSubscriptionAmt, Difference
I know the effort below is not correct. I know I have to do some kind of partition over in the sub queries but I cant put my finger on it
Any help is appreciated
SELECT
[Account ID],
[Account Name],
b.EarlySub,
c.LatestSub,
(c.LatestSub - b.EarlySub / b.EarlySub) * 100 as PercentageChange
FROM
SubTable AS
LEFT JOIN
(SELECT
[Account ID],
SubscriptionAmt AS EarlySub
FROM
SubTable
WHERE
DateKey = MIN(DateKey)) AS b ON a.[Account ID] = b.[Account ID]
LEFT JOIN
(SELECT
[Account ID],
SubscriptionAmt AS LatestSub
FROM
SubTable
WHERE
DateKey = MAX(DateKey)) AS c ON a.[Account ID] = c.[Account ID]
Sample Data:
AccountId AccountName SubscriptionAmt DateKey
----------------------------------------------------
1 Bob's Store 100 201701
1 Bob's Store 200 201702
1 Bob's Store 300 201703
1 Bob's Store 400 201704
Desired Results:
AccountId AccountName EarliestSubAmt LatestSubAmt PercentageChange
------------------------------------------------------------------------
1 Bob's Store 100 400 300%

Answer 1

FULL demonstration:
DECLARE #TABLE TABLE
(
AccountId VARCHAR(50),
AccountName VARCHAR(50),
SubscriptionAmt INT,
DateKey VARCHAR(50)
)
INSERT INTO #TABLE
VALUES('1','Bob''s Store','100','201701'),('1','Bob''s Store','200','201702'),('1','Bob''s Store','300','201703'),('1','Bob''s Store','400','201704')
;
WITH CTE
AS
(
SELECT AccountId,
AccountName,
SubscriptionAmt,
ROW_NUMBER()OVER(PARTITION BY AccountId,AccountName ORDER BY CAST(DateKey+'01' as DATE)) as ForMin,
ROW_NUMBER()OVER(PARTITION BY AccountId,AccountName ORDER BY CAST(DateKey+'01' as DATE) DESC) as ForMAX
FROM #TABLE
)
SELECT A.AccountId,
A.AccountName,
A.SubscriptionAmt as EarliestSubAmt,
B.SubscriptionAmt as LatestSubAmt,
CAST(((B.SubscriptionAmt - A.SubscriptionAmt)/A.SubScriptionAmt ) as varchar(50)) + '%' as PercentageChange
FROM CTE as A
INNER JOIN CTE as B
ON A.AccountId = B.AccountId
AND A.AccountName = B.AccountName
WHERE A.ForMin = 1 AND B.ForMAX = 1

Answer 2

you can get the Min and Max amounts by first getting the min date and the max date per account id using outer apply, then using a case expression to get the min or max amounts
select [AccountId], [AccountName],
MIN(CASE WHEN DateKey = MinDateKey THEN SubscriptionAmt END) as EarliestSubAmt,
MAX(CASE WHEN DateKey = MaxDateKey THEN SubscriptionAmt END) as LatestSubAmt
from SubTable s
outer apply (
select Min(DateKey) MinDateKey, Max(DateKey) MaxDateKey from SubTable t where s.AccountId = t.AccountId
) t
group by [AccountId], [AccountName]
you can wrap all of this to get the percent change.
select *,
((LatestSubAmt-EarliestSubAmt)/EarliestSubAmt) * 100 as PercentageChange
from (
select [AccountId], [AccountName],
MIN(CASE WHEN DateKey = MinDateKey THEN SubscriptionAmt END) as EarliestSubAmt,
MAX(CASE WHEN DateKey = MaxDateKey THEN SubscriptionAmt END) as LatestSubAmt
from SubTable s
outer apply (
select Min(DateKey) MinDateKey, Max(DateKey) MaxDateKey from SubTable t where s.AccountId = t.AccountId
) t
group by [AccountId], [AccountName]
) s

Answer 3

Please use below query . I have considered Account ID as key value for each store and it will not be duplicated. Please test before implementing into any system.
--Data Prep
create table #Test (
AccountId int,
AccountName varchar(max),
SubscriptionAmt int,
DateKey int
)
insert into #Test
Select 1,'Bobs Store',100,201701
union
select 1,'Bobs Store',200,201702
union
select 1,'Bobs Store',300,201703
union
select 1,'Bobs Store',400,201704
--Actual code ****************************************************
select *,
ROW_NUMBER() over(Partition by Accountid order by datekey asc) MinAm,
ROW_NUMBER() over(Partition by Accountid order by datekey desc) MaxAm into #Final
from #Test
Select *,
((LatestSubAmt-EarliestSubAmt)/EarliestSubAmt)*100 as PercentageChange
From (
select
AccountId,
AccountName,
(select SubscriptionAmt from #Final f2 where f1.AccountId=f2.AccountId and f2.MinAm=1) EarliestSubAmt,
(select SubscriptionAmt from #Final f2 where f1.AccountId=f2.AccountId and f2.MaxAm=1) LatestSubAmt
from #Final f1
Where MinAm=1) A
--********************************************************
If you don't want to use sub query
Select Distinct Accountid,
AccountName,
sum(case when minAm=1 then SubscriptionAmt else 0 END) over (Partition by Accountid) EarliestSubAmt ,
sum(case when maxam=1 then SubscriptionAmt else 0 END) over (Partition by Accountid) LatestSubAmt,
((sum(case when maxam=1 then SubscriptionAmt else 0 END) over (Partition by Accountid)-sum(case when minAm=1 then SubscriptionAmt else 0 END) over (Partition by Accountid))
/sum(case when minAm=1 then SubscriptionAmt else 0 END) over (Partition by Accountid))*100 PercentageChange
FRom (
select *,
ROW_NUMBER() over(Partition by Accountid order by datekey asc) MinAm,
ROW_NUMBER() over(Partition by Accountid order by datekey desc) MaxAm
from #Test
)A