The following table shows the symbols used in the explanation of CQL syntax. From here on, Chapters 3 and 4 uses these symbols when explaining CQL syntax.

Table 3-2 Symbols used in the explanation of CQL syntax

Symbol	Meaning	Example
{ }	One of the multiple items enclosed in these symbols must be selected.	{character-string-constant|numeric-constant} Either a character string constant or numeric constant must be entered.
[ ]	Items enclosed in these symbols are optional. If multiple items are listed, all may be omitted or one of them must be selected as in the symbols { }.	[SECOND|MILLISECOND] Both may be omitted, or SECOND or MILLISECOND can be entered.
...	The item preceding this symbol can be repeated as needed.	relation-reference[,relation-reference]... Relation reference may be entered repeatedly.
'(' ')'	The item enclosed in these symbols must be entered as is including the parentheses (( )).	'('TINYINT')' TINYINT must be entered enclosed in parentheses (( )).
'[' ']'	The item enclosed in these symbols must be entered as is including the square brackets ([ ]).	'['window-specification']' Window specification must be entered enclosed in square brackets ([ ]).
::=	The item on the left side of this symbol is defined as the item on the right.	selection-list::=select-expression[,selection-list]
n	Indicates n or more delimiters. If n is omitted, n = 1 is assumed.	NOT{0'('search-condition')'|comparison-predicate} Enter zero or more delimiters between NOT and the (search condition), or enter one or more delimiters between NOT and the comparison predicate.