richard.maw (3/30/2010)
Can anyone give an account of why the semantics of isnull and coalesce (with two args) is different?
Here is a nice article about this: http://blogs.msdn.com/sqltips/archive/2008/06/26/differences-between-isnull-and-coalesce.aspx
COALESCE basically translates to CASE expression and ISNULL is a built-in implemented in the database engine.
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COALESCE is based on the ANSI SQL standard whereas ISNULL is a proprietary TSQL function