CODEWITHSUNDEEP
mysql
bluetxxth
bluetxxth

Reputation: 121

Count unique ids on right table

I have a mysql statement as follows:

SELECT * FROM class_members WHERE class_id = 1;

Which returns the following result:

class_id | user_id
   1     |   2
   1     |   1
   1     |   3
   1     |   5

I want to count all the unique user_ids per class.

Can anyone help?

Thank you

Upvotes: 0

Views: 29

Answers (1)

Quassnoi
Quassnoi

Reputation: 425431

SELECT  class_id, COUNT(DISTINCT user_id)
FROM    mytable
GROUP BY
        class_id

Upvotes: 4

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