SQL Server 2022

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE Example 
(
    Basketld	INT,
    OrderNo	VARCHAR(512),
    BasketSKUs	VARCHAR(512),
    OrderSKUs	VARCHAR(512)
);

INSERT INTO Example (Basketld, OrderNo, BasketSKUs, OrderSKUs) VALUES
	(20009610, 'MFTJZ3', '064008, 064011, 064057, 064074, 064075, 064092, 064093, 064094, 064095, 06...', '226374, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232'),
	(20011137, 'MFTJZ3', '856354, 857133, 857134, 857135, 857511, 857512, 857513, 857530, 857646, 85...', '226374, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232'),
	(20011138, 'MFTJZ3', '055522, 055523, 055524, 055525, 089893, 112935, 119355, 634691, 634692, 65...', '226374, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232'),
	(20011139, 'MFTJZ3', '055522, 055523, 055524, 055525, 089893, 112935, 119355, 634691, 634692, 65...', '055522, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232');

SELECT * FROM Example

;with Baskets as
(
  select Basketld,OrderNo, Value = trim(b.value)
  from Example a
  cross apply string_split(a.BasketSKUs, ',') b
), Orders as
(
  select Basketld,OrderNo, Value = trim(b.value)
  from Example a
  cross apply string_split(a.OrderSKUs, ',') b
)
select
    b.Basketld,
    ItemCount = count(1),
    MatchCount = count(o.value)
from Baskets b
left outer join Orders o
    on b.Basketld = o.Basketld
        and b.Value = o.Value
group by b.Basketld
ORDER BY b.Basketld

Basketld	OrderNo	BasketSKUs	OrderSKUs
20009610	MFTJZ3	064008, 064011, 064057, 064074, 064075, 064092, 064093, 064094, 064095, 06...	226374, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232
20011137	MFTJZ3	856354, 857133, 857134, 857135, 857511, 857512, 857513, 857530, 857646, 85...	226374, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232
20011138	MFTJZ3	055522, 055523, 055524, 055525, 089893, 112935, 119355, 634691, 634692, 65...	226374, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232
20011139	MFTJZ3	055522, 055523, 055524, 055525, 089893, 112935, 119355, 634691, 634692, 65...	055522, 410990, 561242, 569197, 630684, 670071, 685224, 685225, 685226, 706226, 706227, 706228, 706229, 706230, 706231, 706232

Basketld	ItemCount	MatchCount
20009610	10	0
20011137	10	0
20011138	10	0
20011139	10	1

Warning: Null value is eliminated by an aggregate or other SET operation.