Getting both max and min sum values on mysql - mysql

Question

Good day everyone I would like a query that can give me both maximum and minimum sum values. Specifically i have the following tables:
PRODUCT
_____________________________
productID | categoryID| name|
__________|___________|_____|
1 1 "name1"
2 1 "name2"
3 1 "name3"
4 2 "name4"
5 2 "name5"
6 1 "name6"
7 2 "name7"
8 2 "name8"
AND:
PURCHASES
_____________________________
purchaseID | productID| quantity|
___________|___________|_________|
1 1 12
2 2 13
3 4 55
4 4 66
5 5 99
6 6 99
7 5 88
8 7 12
so basically i have to show the product that was bought the most and the product that was bought the least.. T have tried this:
SELECT pr.name, max(sum(p2.quantity))
FROM purchase as p2, product as pr
WHERE p2.IDproduct=pr.IDproduct
Group by p2.IDproduct desc
but I get Error Code 1111: Invalid use of group function.

Answer 1

For max Product
select t.name,max(t.sum1) MaxProduct
FROM
(SELECT a.name, sum(b.quantity) sum1
FROM PRODUCT a
INNER JOIN PURCHASES b
ON a.productID = b.productID
GROUP BY a.productID )t
group by t.name order by MaxProduct desc limit 1
FOR COMBINE RESULT
(select t.name,max(t.sum1) MaxProduct
FROM
(SELECT a.name, sum(b.quantity) sum1
FROM PRODUCT a
INNER JOIN PURCHASES b
ON a.productID = b.productID
GROUP BY a.productID )t
group by t.name order by MaxProduct desc limit 1)
UNION ALL
(select t1.name,min(t1.sum1) MaxProduct
FROM
(SELECT a.name, sum(b.quantity) sum1
FROM PRODUCT a
INNER JOIN PURCHASES b
ON a.productID = b.productID
GROUP BY a.productID )t1
group by t1.name order by MaxProduct asc limit 1)
SQL FIDDLE

Answer 2

Hacky, but it works
(
SELECT
SUM(pur.quantity) quant,
prod.name name
FROM Purchases pur
INNER JOIN Products prod
ON prod.productID = pur.productID
GROUP BY pur.productID
ORDER BY quant DESC
LIMIT 1
)
UNION
(
SELECT
SUM(pur.quantity) quant,
prod.name name
FROM Purchases pur
INNER JOIN Products prod
ON prod.productID = pur.productID
GROUP BY pur.productID
ORDER BY quant ASC
LIMIT 1
)
SQLFiddle

Answer 3

As I received a Cannot perform an aggregate function on an expression containing an aggregate or a subquery as an error error.
For others encountering the problem of using the SUM function inside of a MAX function, but not having the same issue as OP, based on Luv's answer, I was able to convert the following Scalar-valued function:
SELECT #MinMaxValue = MAX(SUM(ArtikelM.Omzet)/SUM(ArtikelM.Aantal))
FROM ArtikelM
INNER JOIN Klanten
ON ArtikelM.KlantenId = Klanten.KlantenId
WHERE ArtikelId = #ArtikelId
AND Klanten.KlantTypeCategorie = #KlantType
AND Klanten.KlantGrootteCategorie = #KlantGrootte
AND ArtikelM.Jaar = #Jaar
to
SELECT #MinMaxValue = MAX(selectedsum.sumx)
FROM (
SELECT SUM(ArtikelM.Omzet)/SUM(ArtikelM.Aantal) AS sumx
FROM ArtikelM
INNER JOIN Klanten
ON ArtikelM.KlantenId = Klanten.KlantenId
WHERE ArtikelId = #ArtikelId
AND Klanten.KlantTypeCategorie = #KlantType
AND Klanten.KlantGrootteCategorie = #KlantGrootte
AND ArtikelM.Jaar = #Jaar
) AS selectedsum
or if ArtikelM.Aantal could be zero
SELECT sumx =
CASE
WHEN SUM(ArtikelM.Aantal) > 0
THEN SUM(ArtikelM.Omzet)/SUM(ArtikelM.Aantal)
ELSE MIN(Leverancier.FactPrijs)
END
FROM ArtikelM
INNER JOIN Leverancier
ON ArtikelM.LevId = Leverancier.LevId
INNER JOIN Klanten
ON ArtikelM.KlantenId = Klanten.KlantenId
WHERE ArtikelId = #ArtikelId
AND Klanten.KlantTypeCategorie = #KlantType
AND Klanten.KlantGrootteCategorie = #KlantGrootte
AND ArtikelM.Jaar = #Jaar
) AS selectedsum
I think this might help out others too

Answer 4

Select max(product_id), min(product_id)
from Purchases Where Product_id In
(select product_id, Sum(quantity) from Purchases Group by product_id)