MySQL 8.0

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select version();


version()


8.0.27


CREATE TABLE table1 (`TYPE` char(1), `rank` INTEGER);

INSERT INTO table1 values
   ('A',1),
   ('A',2),
   ('B',3),
   ('A',4),
   ('B',5),
   ('B',6),
   ('B',7),
   ('A',8);
SELECT `type`,`rank`
FROM (
   SELECT
     `type`,
     lag(`type`) over (order by `rank` desc) as L,
     case when `type`=lag(`type`) over (order by `rank` desc) then 1 else 0 end C,
     `rank`
   FROM table1
   ORDER BY `rank`
) x WHERE c=0


type
rank


A
2

B
3

A
4

B
7

A
8