Recursive CTE

recursive_cte.sql

DECLARE @str varchar(100) = '1721,1603,1063,1683,2049'
DECLARE @delimiter varchar(10) = ','

;

WITH mycte AS
(
    SELECT 0 a, 1 b
    UNION ALL
    SELECT b, CHARINDEX(@delimiter, @str, b) + LEN(@delimiter)
    FROM mycte
    WHERE b > a
)
SELECT SUBSTRING(@str, a,
CASE WHEN b > LEN(@delimiter) 
    THEN b - a - LEN(@delimiter) 
    ELSE LEN(@str) - a + 1 END) value      
FROM mycte WHERE a > 0