Rather than list instances including repeats on one line, you want to list distinct instances and their counts. One way is to do a simple GROUP BY query and in your application layer remove the newlines from the result. Or you can do it in one step.

-- ---------------------------------------------------------------------------
-- Combine Group_Concat() with counts
--
-- from the Artful Common Queries page
-- http://www.artfulsoftware.com/infotree/queries.php
-- ---------------------------------------------------------------------------

-- Rather than list instances including repeats on one line, you want to list
-- distinct instances and their counts. One way is to do a simple GROUP BY query
-- and in your application layer remove the newlines from the result. Or you
-- can do it in one step:

drop table if exists t;

create table t (
  type int(10) ,
  instance int(10)
);

insert into t values
  (1,4),(1,7),(1,9),(1,10),(2,2),(2,3),(2,5),(2,6),(2,8),(3,1),(4,11);

select group_concat( concat( type,'(',qty,')') separator ', ') list
from (
  select type, count(*) qty
  from t
  group by type
) n

-- +------------------------+
-- | list                   |
-- +------------------------+
-- | 1(4), 2(5), 3(1), 4(1) |
-- +------------------------+