I haven't been able to quite figure out what it is you want in the end, but the following code traverses your data in the proper order starting at the top.

Based on this, what is it you are trying to accomplish?

Create table dbo.TestData (

id_task int,

id_fathertask int,

level_task int,

duracion_task int,

percent_task int null,

name_task varchar(24)

);

go

insert into dbo.TestData

values

(1,1,1,76,NULL,'Task 1'),

(2,1,2,60,NULL,'Task,1.1'),

(3,2,3,2,100,'Task,1.1.1'),

(4,2,3,38,NULL,'Task,1.1.2'),

(5,4,4,10,100,'Task,1.1.2.1'),

(6,4,4,22,20,'Task,1.1.2.2'),

(7,4,4,5,35,'Task,1.1.2.3'),

(8,4,4,1,40,'Task,1.1.2.4'),

(9,2,3,20,NULL,'Task,1.1.3'),

(10,9,4,20,20,'Task,1.1.3.1'),

(11,1,2,9,NULL,'Task,1.2'),

(12,11,3,2,0,'Task,1.2.1'),

(13,11,3,7,NULL,'Task,1.2.2'),

(14,13,4,2,50,'Task,1.2.2.1'),

(15,13,4,5,50,'Task,1.2.2.2'),

(16,1,2,10,0,'Task,1.3'),

(17,1,2,20,0,'Task,1.4'),

(18,1,2,6,NULL,'Task,1.5'),

(19,18,3,6,NULL,'Task,1.5.1'),

(20,19,4,6,NULL,'Task,1.5.1.1'),

(21,20,5,6,10,'Task,1.5.1.1.1');

go

with BaseData as (

select

id_task,

id_fathertask,

level_task,

duracion_task,

percent_task,

name_task,

task_level = 1 -- for comparision purposes

from

dbo.TestData

where

id_task = id_fathertask

union all

select

td.id_task,

td.id_fathertask,

td.level_task,

td.duracion_task,

td.percent_task,

td.name_task,

task_level = bd1.task_level + 1

from

dbo.TestData td

inner join BaseData bd1

on (td.id_fathertask = bd1.id_task and td.id_task <> td.id_fathertask)

)

select * from BaseData order by name_task;

go

drop table dbo.TestData;

go