MySQL count number of times a result appears after grouping - mysql

Question

I have a very similar problem to this one:
Count unique occurrences per each distinct variable in MySQL but with a twist.
I'm working with a select statement that shows results much like what the above-mentioned question does.
If I boil down my statement into a simple form for this question my code looks like this:
SELECT
salesman,
brand
FROM
sales
WHERE
sales.date=something
GROUP BY salesman, brand
Resulting in an example output like this:
salesman brand
____ _______
Mark aaa
Mark bbb
Mark ccc
Mark ddd
Jane aaa
Jane bbb
Cody aaa
Without the GROUP BY part the results might look like this:
salesman brand
____ _______
Mark ddd
Jane bbb
Mark aaa
Cody aaa
Mark ddd
Jane aaa
Mark aaa
Jane aaa
Mark ccc
Mark bbb
The twist I have is that I want to count the number of times each brand appears after the grouping and output it in the same table of results.
EG:
salesman brand brand_count
____ _______ _____
Mark aaa 3
Mark bbb 2
Mark ccc 1
Mark ddd 1
Jane aaa 3
Jane bbb 2
Cody aaa 3
I've tried adding count(*) to the SELECT but that only returns the number 2 for salesman Mark with brand aaa and 1 for Cody, which isn't what I'm after.
I want to show for each brand the number of times it appeared in the results.
So brand aaa for example shows 3 times.
I suspect there might be a subquery needed though I'm not sure how it would work.
Any suggestions would be greatly appreciated.
EDIT:
Original MySQL code below in case it helps
select
ARM.SALESMAN AS 'SalesmanNumber',
INM.BRAND AS 'Brand'
from
ARMASTER ARM
LEFT JOIN ARTRAN ART ON ARM.NUMBER = ART.CUST_NO
LEFT JOIN INTRAN INTR ON ART.REF = INTR.REF
LEFT JOIN ARSALECD SALESMAN ON ARM.SALESMAN = SALESMAN.CODE
LEFT JOIN INMASTER INM ON INTR.STOCK_CODE = INM.CODE
where
ARM.AREA = 01
AND ARM.CUSTTYPE <> '99'
AND ARM.SALESMAN NOT IN (24,48,49,50,51,52,71,72,74,90)
AND (
(YEAR(INTR.DATE) = YEAR(#mth) AND MONTH(INTR.DATE) = MONTH(#mth))
OR (YEAR(DATE_ADD(#mth, INTERVAL -1 MONTH)) AND MONTH(INTR.DATE) = MONTH(DATE_ADD(#mth, INTERVAL -1 MONTH)))
OR (YEAR(DATE_ADD(#mth, INTERVAL -2 MONTH)) AND MONTH(INTR.DATE) = MONTH(DATE_ADD(#mth, INTERVAL -2 MONTH)))
)
group by Brand , SalesmanNumber;
I tried making the select part of the statement look like this per Robo suggestion:
ARM.SALESMAN AS 'SalesmanNumber',
INM.BRAND AS 'Brand',
(
SELECT
count(*)
FROM
INMASTER AS s
WHERE
s.BRAND=INMASTER.BRAND
) AS brand_count
But get this error
Error Code: 1054. Unknown column 'INMASTER.BRAND' in 'where clause'
Also, I'm working with an old database version: MySQL 5.1.60

Answer 1

On an older MySQL version you can use:
select s.salesman,s.brand,brand_count
from sales s
inner join (select brand,count(brand) as brand_count
from ( select salesman,brand
from sales
group by salesman,brand
) as tbl
group by brand
) as x on x.brand=s.brand
group by salesman,brand,brand_count
order by s.salesman ;
https://dbfiddle.uk/EevII2mZ
Group by the result , in an outer query count the brand and then use that as a subquery to join with the primary same table

Answer 2

You need to use a subquery:
SELECT
salesman,
brand,
(
SELECT
count(*)
FROM
sales AS s
WHERE
s.brand=sales.brand
) AS brand_count
FROM
sales
WHERE
sales.date=something
GROUP BY salesman, brand

Answer 3

On MySQL v8+, you can use COUNT() OVER () function.
Create table & data example:
CREATE TABLE sales(
salesman VARCHAR(255),
brand VARCHAR(255),
date DATE);
INSERT INTO sales VALUES
('Mark','ddd','2022-10-06'),
('Jane','bbb','2022-10-06'),
('Mark','aaa','2022-10-06'),
('Cody','aaa','2022-10-06'),
('Mark','ddd','2022-10-06'),
('Jane','aaa','2022-10-06'),
('Mark','aaa','2022-10-06'),
('Jane','aaa','2022-10-06'),
('Mark','ccc','2022-10-06'),
('Mark','bbb','2022-10-06');
Query:
SELECT
salesman,
brand,
COUNT(brand) OVER (PARTITION BY Brand) AS brand_count
FROM
sales
WHERE date='2022-10-06'
GROUP BY salesman, brand
ORDER BY salesman DESC, brand
Results:
salesman
brand
brand_count
Mark
aaa
3
Mark
bbb
2
Mark
ccc
1
Mark
ddd
1
Jane
aaa
3
Jane
bbb
2
Cody
aaa
3
Demo fiddle
For older MySQL version:
SELECT t1.salesman, t1.brand, brand_count
FROM sales t1
JOIN
/*this part of the query is just to get the brand_count*/
(SELECT brand, COUNT(*) AS brand_count
FROM
(SELECT salesman, brand
FROM sales
WHERE date='2022-10-06'
GROUP BY salesman, brand) t
GROUP BY brand) t2
/*this part of the query is just to get the brand_count*/
ON t1.brand=t2.brand
WHERE t1.date='2022-10-06'
GROUP BY t1.salesman, t1.brand
ORDER BY t1.salesman DESC, t1.brand;
Demo fiddle