How to Rewrite 'IS DISTINCT FROM' and 'IS NOT DISTINCT FROM' in SQL Server 2008R2?

Replacing "IS DISTINCT FROM" and "IS NOT DISTINCT FROM" in SQL Server 2008R2

Microsoft SQL Server 2008R2 doesn't natively support the standard SQL operators "IS DISTINCT FROM" and "IS NOT DISTINCT FROM." This guide offers equivalent expressions for use in SQL Server 2008R2.

Alternative for "IS DISTINCT FROM"

The "IS DISTINCT FROM" operator returns TRUE if two values are different, or if either value is NULL. Here's the equivalent:

((a != b OR a IS NULL OR b IS NULL) AND NOT (a IS NULL AND b IS NULL))

Alternative for "IS NOT DISTINCT FROM"

The "IS NOT DISTINCT FROM" operator returns TRUE if two values are the same, or if both values are NULL. The equivalent is:

(a = b OR (a IS NULL AND b IS NULL))

Important Considerations

These replacements don't perfectly mirror the behavior of the standard operators, especially regarding NULL handling in comparisons beyond simple equality. However, they provide a practical solution within the limitations of SQL Server 2008R2's data type compatibility. Use caution when applying these alternatives to complex queries.

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