SQL Server 2017

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SELECT *, BINARY_CHECKSUM(a,b) AS bc
FROM (VALUES(1, NULL, 100),
            (2, NULL, NULL),
            (3, 1, 2)) s(id,a,b);


id
a
b
bc


1
null
100
-109

2
null
null
-2147483640

3
1
2
18


SELECT *, BINARY_CHECKSUM(a,b) AS bc
FROM (VALUES(1, NULL, 100),
            (2, NULL, NULL)) s(id,a,b);


id
a
b
bc


1
null
100
100

2
null
null
2147483647


SELECT *, BINARY_CHECKSUM(a,b) AS bc
FROM (VALUES(1, 1, 100),
            (2, 3, 4),(3,1,1)) s(id,a,b);


id
a
b
bc


1
1
100
116

2
3
4
52

3
1
1
17


SELECT *, BINARY_CHECKSUM(a,b) AS bc
FROM (VALUES(1, 1, 100),
            (2, 3, 4)) s(id,a,b);


id
a
b
bc


1
1
100
116

2
3
4
52

id	a	b	bc
1	null	100	-109
2	null	null	-2147483640
3	1	2	18

id	a	b	bc
1	null	100	100
2	null	null	2147483647