PL/SQL User's Guide and Reference

Literals

Description

A literal is an explicit numeric, character, string, or Boolean value not represented by an identifier. The numeric literal 135 and the string literal 'hello world' are examples. For more information, see "Literals"

Syntax

numeric_literal ::=

[+ | -]{integer | real_number}

integer ::=

digit[digit]...

real_number ::=

{  integer[.integer]
 | integer.
 | .integer}[{E | e}[+ | -]integer]

character_literal ::=

{'character' | ''''}

string_literal ::=

'{character[character]... | ''['']...}'

boolean_literal ::=

{TRUE | FALSE | NULL}

Keyword and Parameter Description

integer

This is an optionally signed whole number without a decimal point.

real_number

This is an optionally signed whole or fractional number with a decimal point.

digit

This is one of the numerals 0 .. 9.

char

This is a member of the PL/SQL character set. For more information, see "Character Set"

TRUE, FALSE

This is a predefined Boolean value.

NULL

This is a predefined non-value, which stands for a missing, unknown, or inapplicable value.

Usage Notes

Two kinds of numeric literals can be used in arithmetic expressions: integers and reals. Numeric literals must be separated by punctuation. Space characters can be used in addition to the punctuation.

A character literal is an individual character enclosed by single quotes (apostrophes). Character literals include all the printable characters in the PL/SQL character set: letters, numerals, spaces, and special symbols. PL/SQL is case sensitive within character literals. So, for example, PL/SQL considers the literals 'Q' and 'q' to be different.

A string literal is a sequence of zero or more characters enclosed by single quotes. The null string ('') contains zero characters. To represent an apostrophe within a string, write two single quotes. PL/SQL is case sensitive within string literals. So, for example, PL/SQL considers the literals 'white' and 'White' to be different.

Also, trailing blanks are significant within string literals, so 'White' and 'White ' are different. How a string literal compares to a variable does not depend on the variable; trailing blanks in a literal are never trimmed.

Unlike the non-value NULL, the Boolean values TRUE and FALSE cannot be inserted into a database column.

Examples

Several examples of numeric literals follow:

25   6.34   7E2   25e-03   .1   1.   +17  -4.4

Several examples of character literals follow:

'H'   '&'   ' '   '9'   ']'   'g'

A few examples of string literals follow:

'$5,000'
'02-AUG-87'
'Don''t leave without saving your work.'