Reputation: 6537
Table works(emNo, comNo, salary)
.
I can get distinct comNo using "select distinct comNo from works". Suppose it gives me a column with 5 rows. How do I count "
emNo`" for each of those rows?
Upvotes: 3
Views: 87
Reputation: 56769
You can use GROUP BY
to aggregate per type of comNo
.
SELECT
comNo,
count(emNo)
FROM
works
GROUP BY
comNo
This will return one row per distinct value of comNo
along with the count of records per group.
Demo: http://www.sqlfiddle.com/#!2/4f5df/1
Upvotes: 5