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  • Dustin Waybright thinks this is interesting:

If the source attribute col1 is defined as NOT NULL, both expressions will produce an attribute in the result table defined as NOT NULL. However, if the source attribute col1 is defined as allowing NULLs, COALESCE will create a result attribute allowing NULLs, whereas ISNULL will create one that disallows NULLs.

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Cover of Training Kit (Exam 70-461): Querying Microsoft® SQL Server® 2012

Note

When using a SELECT INTO