SQL syntax is presented in modified BNF notation.
The meta-symbols of BNF are listed in the following table.
| Symbol | Meaning | 
|---|---|
| | | Or. Choose one of the items. | 
| [ ] | Encloses optional items. | 
| * | Flags items that you can repeat 0 or more times. Has a special meaning in some SQL statements. | 
| { } | Groups required items so that they can be marked with the symbol |. Has a special meaning in JDBC escape syntax (see JDBC escape syntax). | 
| ( ) . , | Other punctuation that is part of the syntax. | 
CREATE [ UNIQUE ] INDEX indexName ON tableName ( simpleColumnName [ , simpleColumnName ]* )