create table T (a varchar(64), b varchar(64));
insert into T values ('1,2,3', 'A,B,C');
-- SELECT value FROM STRING_SPLIT('Lorem ipsum dolor sit amet.', ' ');
SELECT A.value, B.value FROM (
SELECT *
FROM T
CROSS APPLY STRING_SPLIT(a, ',', 1)
) A,
(
SELECT *
FROM T
CROSS APPLY STRING_SPLIT(b, ',', 1)
) B
WHERE A.ordinal = B.ordinal