How to sum in sql with a DISTINCT clause - sql

Question

In the following example SQL Fiddle
How should I proceed to obtain the cumulative price for each 'Phone' instead of obtaining the last value?
In the example given below, I would need the following table to be produced:
Phone Price Purchases
50 35 3
51 50 2
52 99 3
55 21 2
53 16 2
54 21 1
56 16 1
58 22 1
57 10 2
This is to be done in SQL-Server 2012
Thanks in advance.

Answer 1

You should be able to use the following:
select c1.phone,
c2.TotalPrice,
c1.purchases
from supportContacts c1
inner join
(
select
max(Fecha) maxFecha,
sum(price) TotalPrice,
phone
from supportContacts
group by phone
) c2
on c1.phone = c2.phone
and c1.Fecha = c2.maxFecha
order by c1.phone;
See SQL Fiddle with Demo.
The subquery gets the Total sum for each phone along with the the max fecha associated with the phone. You then use this and join back to your table on both the phone and the fecha to get the result.

Answer 2

I don't have a SQL Server 2012 handy, but give this a shot:
select
phone,
purchases,
price,
sum(price) over (partition by phone order by phone, price) as running_sum_purchases
FROM
supportContacts

Answer 3

Isn't it just...
SELECT Phone, Sum(Price), Count(Purchases)
FROM supportContacts
GROUP BY Phone
ORDER BY 1
.. or have I missed something?
http://sqlfiddle.com/#!6/7b36f/41
50 35 3
51 50 4
52 99 3
53 16 2
54 21 2
55 21 1
56 16 1
57 10 1
58 22 2
If you need more details per phone, you can add a subquery :
SELECT
Phone,
Sum(Price) as Total,
Count(Purchases) as Purchase_Count,
(SELECT TOP 1 Price
FROM supportContacts sc2
WHERE sc2.phone=sc1.phone
ORDER BY fecha DESC
) as Most_Recent
FROM supportContacts sc1
GROUP BY Phone
ORDER BY Phone
or, for the actual requirement which I've finally worked out :)
SELECT
Phone,
Sum(Price) as Total,
Count(Purchases) as Purchase_Count,
(SELECT Purchases
FROM supportContacts sc2
WHERE sc2.phone=sc1.phone
AND sc2.Fecha=
(SELECT Max(Fecha)
FROM supportContacts sc3
WHERE sc3.phone=sc1.phone
)
) as Last_Purchase
FROM supportContacts sc1
GROUP BY Phone
ORDER BY Phone
.. which is starting to get quite unwieldy, there's probably an optimisation possible, but I'm losing the will to play... LOL
But thanks for the cerebral exercise of trying to do it this way :)
EDIT
I would probably have done it like this, if it had been me...
http://sqlfiddle.com/#!6/7b36f/98
With PhoneGroup as
( SELECT
Phone,
Sum(Price) as Total_Price,
Max(Fecha) as Last_Fecha
FROM supportContacts
GROUP BY Phone
)
SELECT
Phone, Total_Price,
(SELECT Purchases
FROM supportContacts sc2
WHERE sc2.phone=PhoneGroup.phone
AND sc2.Fecha=PhoneGroup.Last_Fecha
) as Last_Purchase
FROM PhoneGroup
ORDER BY Phone