Postgresql Literals
PostgreSQL: Literals
In this PostgreSQL post explains how to use literals (string, number, date, 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, date and time literals and boolean literals.
String Literals
String literals are always surrounded by single quotes ('). For example:
| Example | Explanation |
|---|---|
| 'AODBA.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 |
