Postgres 11

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create table tickets (id int, customer text, status smallint);


CREATE TABLE


insert into tickets values
(1, 'A', 0),
(2, 'A', 0),
(3, 'B', 0),
(4, 'B', 0),
(5, 'A', 0),
(6, 'B', 1),
(7, 'C', 0),
(8, 'B', 0),
(9, 'A', 0),
(10, 'B', 0),
(11, 'A', 1),
(12, 'A', 1),
(13, 'A', 1);

INSERT 0 13


SELECT customer,	status, COUNT(*) FROM (
select t.*,
             (row_number() over (partition by customer order by id) -
              row_number() over (partition by customer, status order by id)
             ) as grp
      from tickets t
) X
GROUP BY customer,	status, grp
ORDER BY customer,	max(id)


customer
status
count


A
0
4

A
1
3

B
0
2

B
1
1

B
0
2

C
0
1



SELECT 6