Netezza Performance Server SQL lexical structure

An SQL statement is a sequence of commands. Each command consists of a sequence of tokens that are terminated by an optional semicolon with the end of the input that terminates the command.

Tokens can be:
Words with a fixed meaning in SQL.
Names of users, tables, columns, or other database objects.
Strings, integers, and floating-point numbers.
An arbitrary sequence of characters that begins with double dashes and extending to the end of the line.
A rule that restricts the value for one or more columns in a table. Netezza Performance Server does not support constraint checking and referential integrity.