An alias is a feature of SQL that is supported by most, if not all, relational database management systems (RDBMSs). Aliases provide database administrators, as well as other database users, with the ability to reduce the amount of code required for a query, and to make queries simpler to understand. In addition, aliasing can be used as an obfuscation technique to protect the real names of database fields. Using a table alias: SELECT D.DepartmentName FROM Department AS D We can also write the same query like this (Note that the AS clause is omitted this time): A column alias is similar: