Carlo Romagnano (11/3/2009)
Noel McKinney (11/3/2009)
This is the main reason I make it a habit to use COALESCE rather than ISNULL unless there's a reason I need the behavior of ISNULL.I prefer ISNULL because of performance.
Interesting, I can't recall coming across references to performance comparisons between COALESCE and ISNULL, but yes, there does seem to be a slight advantage in CPU time with ISNULL that could be noticed over a very large number of rows. However, in my environment, preventing unintended truncation of string values is more important than slight performance gains.