LPAD and RPAD functions

These functions prepend or append characters to a string, based on a specified length.

Syntax

LPAD (string1, length, [ string2 ])

RPAD (string1, length, [ string2 ])

Arguments

string1

A character string or an expression that evaluates to a character string, such as the name of a character column.

length

An integer that defines the length of the result of the function. The length of a string is based on the number of characters, not bytes, so that multi-byte characters are counted as single characters. If string1 is longer than the specified length, it is truncated (on the right). If length is a negative number, the result of the function is an empty string.

string2

One or more characters that are prepended or appended to string1. This argument is optional; if it is not specified, spaces are used.

Return type

These functions return a VARCHAR data type.

Examples

Truncate a specified set of event names to 20 characters and prepend the shorter names with spaces:

select lpad(eventname,20) from event
where eventid between 1 and 5 order by 1;

 lpad
--------------------
              Salome
        Il Trovatore
       Boris Godunov
     Gotterdammerung
La Cenerentola (Cind
(5 rows)

Truncate the same set of event names to 20 characters but append the shorter names with 0123456789.

select rpad(eventname,20,'0123456789') from event
where eventid between 1 and 5 order by 1;

 rpad
--------------------
Boris Godunov0123456
Gotterdammerung01234
Il Trovatore01234567
La Cenerentola (Cind
Salome01234567890123
(5 rows)