Here is one approach
DECLARE @InitialCount INT
DECLARE @FinalCount INT
SET @InitialCount = 1
SET @FinalCount = 9999
WHILE @InitialCount <= @FinalCount
BEGIN
INSERT INTO tblAssest
SELECT RIGHT('000' + CAST(@InitialCount AS VARCHAR),4)
SET @InitialCount = @InitialCount + 1
END
SELECT * FROM tblAssest