sp_validname is used to check valid SQL Server identifier names.
All nonbinary and nonzero data, including Unicode data that can be stored by using the nchar, nvarchar, or ntext data types, are accepted as valid characters for identifier names.
sp_validname [@name =] 'name'
[, [@raise_error =] raise_error]
[@name =] 'name'
Is the name of the identifier for which to check validity. name is sysname, with no default. name cannot be NULL, cannot be an empty string, and cannot contain a binary-zero character.