Group by with diff percentage MySQL - mysql

Question

I have been trying to query the increase percentage of a product grouped in certain range depending on the actual increase for each run. So for example I have the following table schema
Now, if I query the increase percent I would get something like:
SELECT *, (((newPrice - price)/price) * 100 ) as PERCENTAGE FROM Product
What Im trying to obtain is to group the values within a particular range depending on the calculated increase. So for this run something like this:
| Range | #COUNT |
| 0-10% | 3 |
| 30-40% | 1 |
and more ranges and products if existing
I have tried:
Select *, COUNT(idProduct) AS COUNT FROM Product
where (((newPrice - price)/price) * 100 ) BETWEEN 0 AND 10
which gives me:
But I need to configure the query in a way it can determine a reasonable percent range (i.e Without hard coding the values BETWEEN 0 AND 10) and group the values in there for different runs. Any ideas?
Thank you!
product table
CREATE TABLE `product` (
`idproduct` INT NOT NULL ,
`description` VARCHAR(45) NULL ,
`price` INT NULL ,
`newPrice` INT NULL ,
PRIMARY KEY (`idproduct`) );

Answer 1

You could group by 10% percentage bands:
SELECT floor((newPrice - price) / price * 10) * 10 as LowerBound
, floor((newPrice - price) / price * 10) * 10 + 10 as HigherBound
, count(*) as Count
FROM Product
GROUP BY
floor((newPrice - price) / price * 10)
Multiplying by 10 and rounding down should create one group per 10 percentage points.

Answer 2

SELECT
r.RangeValue,
COUNT(*) AS CountofProducts
FROM (SELECT
CASE WHEN (((newPrice - price)/newPrice) * 100 ) <= 10 THEN
'0-10%'
WHEN (((newPrice - price)/newPrice) * 100 ) <= 20 THEN
'10-20%'
WHEN (((newPrice - price)/newPrice) * 100 ) <= 30 THEN
'20-30%'
WHEN (((newPrice - price)/newPrice) * 100 ) <= 40 THEN
'30-40%'
ELSE
'40+%'
END AS RangeValue
FROM Product) r
GROUP BY r.RangeValue

Answer 3

Its simple
SELECT count(*) as items, (((newPrice - price)/newPrice) * 100 ) as PERCENTAGE ,
IF (
((newPrice - price)/newPrice* 100) >=0 &&
((newPrice - price)/newPrice* 100) <=10 ,
"0 - 10%" ,
IF (
((newPrice - price)/newPrice* 100) >=11 &&
((newPrice - price)/newPrice* 100) <=30 ,
"10 - 30%",
so on....
)
) AS 'range'
FROM Product
group by range
Basically, you have to use nested if() statements and inside them you put the ranges.
Then give it a meaningful alias. You can then group by the alias.