simpe sql cursor

gistfile1.sql

DECLARE @eNum FLOAT
DECLARE @dNum NVARCHAR(10)
DECLARE @tNum FLOAT
DECLARE @level INT
DECLARE @counter INT

DECLARE @t TABLE (
  id INT
  ,eNum FLOAT
 ,dNum NVARCHAR(10)
 ,tNum FLOAT
 ,[level] INT
);
DECLARE @data TABLE (
  eNum FLOAT
 ,dNum NVARCHAR(10)
 ,tNum FLOAT
 ,[level] INT
);

INSERT INTO @data
    values
(1.1,	'1.1.1',1.2),
(1.2,	'1.2.1',2.1),
(1.3,	'1.3.3',(null)),
(1.3,	'1.3.12',(NULL)),
(1.3,	'1.3.11',(null)),
(1.3,	'1.3.15',(null)),
(1.3,	'1.3.8',(null)),
(1.3,	'1.3.2',(null)),
(1.3,	'1.3.13',(null)),
(1.3,	'1.3.14',(null)),
(1.3,	'1.3.7',(null)),
(1.3,	'1.3.9',(null)),
(1.3,	'1.3.5',(null)),
(1.3,	'1.3.6',(null)),
(1.3,	'1.3.10',(null)),
(1.3,	'1.3.1',(null)),
(1.3,	'1.3.4',(null)),
(2.1,	'2.1.4',2.2),
(2.1,	'2.1.3',2.2),
(2.1,	'2.1.1',2.2),
(2.1,	'2.1.6',2.2),
(2.1,	'2.1.2',2.2),
(2.1,	'2.1.7',2.2),
(2.1,	'2.1.5',2.1),
(2.2,	'2.2.18',	3.1),
(2.2,	'2.2.5',	3.1),
(2.2,	'2.2.15',	3.1),
(2.2,	'2.2.4',	3.1),
(2.2,	'2.2.12',	(null)),
(2.2,	'2.2.7',	3.1),
(2.2,	'2.2.19',	3.1),
(2.2,	'2.2.21',	3.1),
(2.2,	'2.2.11',	2.1),
(2.2,	'2.2.16',	3.1),
(2.2,	'2.2.13',	(null)),
(2.2,	'2.2.2',	3.1),
(2.2,	'2.2.6',	3.1),
(2.2,	'2.2.1',	3.1),
(2.2,	'2.2.20',	3.1),
(2.2,	'2.2.14',	3.1),
(2.2,	'2.2.17',	3.1);
  
/*Объявляем курсор*/
DECLARE @CURSOR CURSOR
/*Заполняем курсор*/
SET @CURSOR = CURSOR SCROLL
FOR SELECT
  *
FROM @data ORDER BY eNum, dNum

OPEN @CURSOR

FETCH NEXT FROM @CURSOR INTO @eNum, @dNum, @tNum, @level
SET @counter = 0;

INSERT INTO @t (id, eNum, dNum, tNum, [level])
              SELECT
                @counter
               ,@eNum
               ,@dNum
               ,@tNum
               ,@level

WHILE @@fetch_status = 0
  BEGIN

  IF NOT EXISTS (SELECT
        1
      FROM @t
      WHERE eNum = @tNum)
        BEGIN
          SET @counter = @counter +1
          INSERT INTO @t (id, eNum, dNum, tNum, [level])
              SELECT
                @counter
                ,eNum
               ,dNum
               ,tNum
               ,1 + @level
              FROM @data d
              WHERE d.eNum = @tNum
        END

  FETCH NEXT FROM @CURSOR INTO @eNum, @dNum, @tNum, @level
END
CLOSE @CURSOR

SELECT
  *
FROM @t