SQL查询在哪里和不同

Question

I have the following sql query which gets back unique days from a column of time stamp values for a particular user. What I am trying to get back is the count of timestamp values for each unique day for a particular user.

 select distinct DAY(time) from users_has_activities
 where usersID = 47;

Answer 1

Using a count COUNT(column_name) with a GROUP BY should do the trick:

SELECT DAY(time), COUNT(DAY(time))
FROM users_has_activities
WHERE usersID = 47
GROUP BY DAY(time);

Answer 2

select count(distinct DAY(time) )
from users_has_activities
where usersID = 47;

Answer 3

Use groupby clause to get count so it would loook something like followin:

select DAY(time), count(1)
from users_has_activities
group by DAY(time);