31 Oct Sql server tutorial 20 Appendices
The SQL standard defines a set of reserved keywords and nonreserved keywords that
are used within your SQL statements. You cannot use reserved keywords as
identifiers. In addition, it is generally a good idea to avoid using nonreserved keywords.
Note that the SQL standard warns that it makes no guarantees about what keywords might
be added to the standard in the future. As a result, an identifier you use in a current
database might not be usable in future releases of SQL. You can avoid conflicts with
future reserved keywords by adding a digit or an underscore to your identifiers, especially
those composed of only a single word, and by not beginning an identifier with current_,
session_, system_, or timezone_, or ending an identifier with _length.
Various SQL implementations include additional keywords and reserved words that cannot be used as identifiers.
Always check your product documentation.
SQL Reserved Keywords