MySQL: Aggregating counts - mysql

Question

I'm trying to find how many companies had sales in a specific segment. I've managed to get a count of the sales entries (5), but I can't seem to aggregate by the product segment as well. Please see this simplification:
http://sqlfiddle.com/#!9/685cb/1
CREATE TABLE Table1
(`company` text, `sales` int, `segment` text)
;
INSERT INTO Table1
(`company`, `segment`, `sales`)
VALUES
('ACME',10,100),
('ACME',11,100),
('HAL',10,25),
('HAL',13,25),
('GEN',11,50)
;
SELECT COUNT(company) AS companies,
CASE
WHEN segment IN (10, 11, 12, 13, 14, 15, 16)
THEN 'Product segment A'
WHEN segment IN (20, 21, 22)
THEN 'Product segment B'
WHEN segment IN (30)
THEN 'Product segment C'
END AS grp, SUM(sales) AS sum_sales
FROM Table1
WHERE
(company LIKE '%ACME%'
OR company LIKE '%HAL%'
OR company LIKE '%GEN%'
)
AND
segment IN (10, 11, 12, 13, 14, 15 ,16, 20, 21, 22, 30)
GROUP BY grp
ORDER BY grp
;
The goal is to get "companies" to show 3, as there are three companies that had sales in segment A.

Answer 1

You could use the distinct modifier in the count function to get the number of different entries:
SELECT COUNT(DISTINCT company) AS companies,
-- Here -----^
CASE
WHEN segment IN (10, 11, 12, 13, 14, 15, 16)
THEN 'Product segment A'
WHEN segment IN (20, 21, 22)
THEN 'Product segment B'
WHEN segment IN (30)
THEN 'Product segment C'
END AS grp, SUM(sales) AS sum_sales
FROM Table1
WHERE
(company LIKE '%ACME%'
OR company LIKE '%HAL%'
OR company LIKE '%GEN%'
)
AND
segment IN (10, 11, 12, 13, 14, 15 ,16, 20, 21, 22, 30)
GROUP BY grp
ORDER BY grp
;
SQLFiddle