The SQL statements available within the Natural programming language comprise two different syntax sets:

• Common Set
  The Common Set basically corresponds to the standard SQL syntax definitions and is provided for each SQL-compliant database system supported by Natural. The Common Set is valid against all SQL databases.

• Extended Set
  The Extended Set, in addition, provides special enhancements to the Common Set to support specific features of the supported database systems. Currently, the Extended Set is partly available and is valid against Db2 databases only.

The Natural SQL statements documentation mainly describes the Natural SQL Common Set. The statement syntax adheres as far as possible to the syntax described in the relevant literature on SQL; please, refer to this literature for further details.