I want to find all the hackers who made at least 1 submission each day.

Table looks like: id, date.

```
1, 2016-01-01
2, 2016-01-01
3, 2016-01-01
1, 2016-01-02
2, 2016-01-02
1, 2016-01-03

```

So the output should be:
1
Since 1 has made submission on all the day.

What I have tried is:

```
Select id from table 
group by id
having count(*)=3 /* Since number of days are 3 */

```

However this is incorrect because a hacker can make multiple submissions on a day. 
Example where my query will fail:

```
1, 2016-01-01
2, 2016-01-01
3, 2016-01-01
3, 2016-01-01
3, 2016-01-01
1, 2016-01-02
2, 2016-01-02
1, 2016-01-03

```

After this is solved, the original question is:

Write a query to print total number of unique hackers who made at least submission each day (starting on the first day of the contest), and find the hacker\_id and name of the hacker who made maximum number of submissions each day. If more than one such hacker has a maximum number of submissions, print the lowest hacker\_id. The query should print this information for each day of the contest, sorted by the date