Koen Verbeeck (2/2/2012)
SQL Kiwi (2/2/2012)
An article about clearly documented behaviour, and no mention of the more serious problems with COALESCE? Poor.Now you make me curious. Which issues are you referring to? A quick Google search tells me that datatype precedence is important for COALESCE.
SELECT COALESCE((SELECT CASE WHEN RAND() <= 0.5 THEN 999 END), 999);
SELECT ISNULL((SELECT CASE WHEN RAND() <= 0.5 THEN 999 END), 999);
https://connect.microsoft.com/SQLServer/feedback/details/546437/coalesce-subquery-1-may-return-null
Paul White
SQLPerformance.com
SQLkiwi blog
@SQL_Kiwi