GaussDB(DWS) SQL Syntax

To better understand how to use the syntax, you can refer to the following description of SQL syntax text conventions.

**Table 1** SQL Syntax Description
Format	Description
Uppercase characters	Keywords must be in uppercase.
Lowercase characters	Parameters must be in lowercase.
[ ]	Optional syntax item. Items in brackets [] are optional.
{ }	Mandatory syntax item.
...	Preceding elements can appear repeatedly.
[ x \| y \| ... ]	One item is selected from two or more options or no item is selected.
{ x \| y \| ... }	One item is selected from two or more options.
[x \| y \| ... ] [ ... ]	You can choose either multiple parameters or no parameters. If you choose multiple parameters, simply separate them with spaces.
[ x \| y \| ... ] [ ,... ]	You can choose either multiple parameters or no parameters. If you choose multiple parameters, simply separate them with commas (,).
{ x \| y \| ... } [ ... ]	You must select at least one parameter. If you select multiple parameters, separate them with spaces.
{ x \| y \| ... } [ ,... ]	You must select at least one parameter. If you select multiple parameters, separate them with commas (,).