Variable Naming Convention

first character can be alphabetic character, _, @. Followed by alphabetic, numeric, or the character $, #, @, _, ¥ (yen), or £ (pound sterling).

@@ is reserved for global variables, which are system-defined variables that Adaptive Server automatically updates.

select @@version

@ sign as the first character of an identifier indicates a local variable.

Temporary table names must either begin with # (the pound sign), if they are created outside tempdb, or be preceded by “tempdb.”