What is difference between != and <> in sql server [duplicate]

Answer 1

Most of the databases support both != and <> as not equal comparison operators. <> means either less than or greater than (i.e. not equal to) and was introduced because not all the keyboards used to have the exclamation ! key (a long time ago). Some databases like Oracle also support ^= for not equals.

Answer 2

There is no difference. You can use both in MSSQL.

The MSSQL doc says:

!= functions the same as the <> (Not Equal To) comparison operator.

But <> is defined in the ANSI 99 SQL standard and != is not. So not all DB engines may support it and if you want to generate portable code I recommend using <>.