MySQL 5.5

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create table data
(tname varchar(20),
tlast int);
insert into data values ('Alex', 50);
insert into data values ('Blue', 10),('Blue', 10);
insert into data values  ('Eva', 201), ('Eva', 301), ('Eva', 401);
insert into data values ('rex0220', 100), ('rex0220', 200), ('rex0220', 200);
select * from data
order by tname,tlast


tname
tlast


Alex
50

Blue
10

Blue
10

Eva
201

Eva
301

Eva
401

rex0220
100

rex0220
200

rex0220
200


DELETE FROM data
WHERE tlast NOT IN (
SELECT * FROM (
SELECT MIN(tlast) FROM data 
GROUP BY tname
) AS A)
SELECT *
FROM data
ORDER BY tname,tlast


tname
tlast


Alex
50

Blue
10

Blue
10

Eva
201

rex0220
100

tname	tlast
Alex	50
Blue	10
Blue	10
Eva	201
Eva	301
Eva	401
rex0220	100
rex0220	200
rex0220	200