Selecting duplicate entries from a table and getting all the fields from the duplicate rows

I have a table like this.

id  day1    day2    day3
1   411     523     223
2   413     554 开发者_Go百科    245
3   417     511     209
4   420     515     232
5   422     522     212
6   483     567     212
7   456     512     256
8   433     578     209
9   438     532     234
10  418     555     223
11  460     510     263
12  453     509     245
13  441     524     233
14  430     543     261
15  456     582     222
16  444     524     241
17  478     511     211
18  421     583     222

I want to select all the IDs that have duplicate values in day2. I'm doing

select day2,count(*) from resultater group by day having count(*)>1;

Is it possible to list all the IDs within the groups?

select day2,count(*), group_concat(id)
    from resultater
    group by day
    having count(*)>1;

should do the trick.