Literals
This PostgreSQL tutorial explains how to use literals (string, number, ate, time, and boolean literals) in PostgreSQL with examples.
Description
In PostgreSQL, a literal is the same as a constant. We'll cover several types of literals - string literals, number literals, ate and time literals and boolean literals.
String Literals
String literals are always surrounded by single quotes ('). For example:
|
Example |
Explanation |
|
'fastread.aitechtonic.com' |
String literal with single quotes |
|
'Tech on the Net' |
String literal with single quotes |
Number Literals
Number literals can be either positive or negative numbers that are exact or floating point values. If you do not specify a sign, then a positive number is assumed. Here are some examples of valid number literals:
|
Example |
Explanation |
|
25 |
Integer literal with no sign (positive sign is assumed) |
|
+25 |
Integer literal with positive sign |
|
-25 |
Integer literal with negative sign |
|
25e-04 |
Floating point literal |
|
25.607 |
Decimal literal |
Date and Time Literals
Date and time literals can be expressed as either strings or numbers. Here are some examples of valid date and time literals:
|
Example |
Explanation |
|
'2014-11-25' |
Date literal formatted as 'YYYY-MM-DD' |
|
'20141125' |
Date literal formatted as 'YYYYMMDD' |
|
20141125 |
Date literal formatted as YYYYMMDD |
|
'14-11-25' |
Date literal formatted as 'YY-MM-DD' |
|
'141125' |
Date literal formatted as 'YYMMDD' |
|
141125 |
Date literal formatted as YYMMDD |
|
'2014-11-25 11:49:36' |
Datetime literal formatted as 'YYYY-MM-DD HH:MM:SS' |
|
'20141125114936' |
Datetime literal formatted as 'YYYYMMDDHHMMSS' |
|
20141125114936 |
Datetime literal formatted as YYYYMMDDHHMMSS |
|
'14-11-25 11:49:36' |
Datetime literal formatted as 'YY-MM-DD HH:MM:SS' |
|
'141125114936' |
Datetime literal formatted as 'YYMMDDHHMMSS' |
|
141112514936 |
Datetime literal formatted as YYMMDDHHMMSS |
|
'0 11:49:36' |
Time literal formatted as 'D HH:MM:SS' where D can be a day value between 0 and 34 |
|
'11:49:36' |
Time literal formatted as 'HH:MM:SS' |
|
'11:49' |
Time literal formatted as 'HH:MM' |
|
'0 11:49' |
Time literal formatted as 'D HH:MM' where D can be a day value between 0 and 34 |
|
'0 11' |
Time literal formatted as 'D HH' where D can be a day value between 0 and 34 |
|
'36' |
Time literal formatted as 'SS' |
|
114936 |
Time literal formatted as HHMMSS |
|
4936 |
Time literal formatted as MMSS |
|
36 |
Time literal formatted as SS |
Boolean Literals
Boolean literals are values that evaluate to either 1 or 0. Here are some examples of valid boolean literals:
|
Example |
Explanation |
|
1 |
Evaluates to 1 |
|
TRUE |
Evaluates to 1 |
|
true |
Evaluates to 1 |
|
0 |
Evaluates to 0 |
|
FALSE |
Evaluates to 0 |
|
false |
Evaluates to 0 |