-- create test table

CREATE TABLE `tt` (

`seq` varchar(6) default NULL,

`parent_seq` varchar(6) default NULL,

`ttext` varchar(26) default NULL

);

-- insert test data

INSERT INTO tt( seq, parent_seq, ttext )

VALUES ('1', '', 'bgb'), ('', '1 - 1', 'aa'), ('', '1 - 2', 'cdc'), ('2', '', 'gg'), ('', '2 - 1', 'kk'), ('', '2 - 2', 'kgk'), ('3', '', 'asd'), ('', '3 - 1', 'ga'), ('', '3 - 2', 'ggaa'), ('', '3 - 3', 'agga');

-- wanted select statement

SELECT seq, parent_seq, ttext

FROM(

(

SELECT seq AS seqg, seq, parent_seq, ttext

FROM tt

ORDER BY seq DESC

LIMIT 2

)

UNION ALL

(

SELECT SUBSTRING_INDEX(children.parent_seq, ' ', 1 ) AS seqg, children.seq, children.parent_seq, children.ttext

FROM (

SELECT seq

FROM tt

ORDER BY seq DESC

LIMIT 2

) AS parent

INNER JOIN tt AS children ON parent.seq = SUBSTRING_INDEX(children.parent_seq, ' ', 1 )

)

) AS bb

ORDER BY seqg DESC, parent_seq;