What is the difference between <> and != operators in SQL?

Practically, there is no difference between <> and != in SQL as both of them are making the NOT EQUAL comparison. The only technical difference would be that <> is supported by all SQL flavors as it is the ANSI/SQL 92 standard. Despite not being part of a standard, != is still widely supported and is available in almost all mainstream SQL flavors. So feel free to use any of them.