ISNULL vs COALESCE: Not as Interchangeable as They Look
ISNULL and COALESCE differ on result type, truncation, nullability, and how often they evaluate their input. When to use each.
ISNULL Truncates Your Replacement Value; COALESCE Doesn’t
ISNULL and COALESCE look like the same function wearing different names. Both take a value, both give you something else when that value is NULL. They differ in how they decide the type of what…