MySQL 8.0

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create table events (id int, event varchar(10));
insert into events values
(22, 'a'),
(23, 'bb'),
(24, 'bb'),
(25, 'ccc'),
(26, 'ccc'),
(27, 'ccc');
select event, group_concat(id, ',') ids, count(*) cnt
from   events
group by event


event
ids
cnt


a
22,
1

bb
23,,24,
2

ccc
25,,26,,27,
3