isnull vs is null

Question

I have noticed a number of queries at work and on SO are using limitations in the form:

isnull(name,\'\') <> \'\'

Is there a particul

Answer 1

isnull(name,'') <> :name is shorthand for (name is null or name <> :name) (assuming that :name never contains the empty string, thus why shorthands like this can be bad).

Performance-wise, it depends. or statements in where clauses can give extremely bad performance. However, functions on columns impair index usage. As usual: profile.