Skip to main content
Documents
Basic SyntaxMath FunctionsDate FunctionsJSON FunctionsDatabasesTables & Schema ManagementString FunctionsTriggersIndexes

PostgreSQL RPAD

The PostgreSQL `RPAD` function is a string function used to right-pad a string with a specified set of characters to a certain length. This function is helpful in formatting output where fixed-width strings are required.

Usage

The `RPAD` function is typically used when you need a string to be a specific length, often for alignment purposes in text processing or report generation. It pads the original string with a specified character or set of characters until the desired length is reached.

RPAD(source_string, length, padding_string)
  • source_string: The initial string to be padded.
  • length: The total length of the result string after padding.
  • padding_string: The string used for padding (optional, defaults to a space if not specified).

Behavior

  • If the length is less than or equal to the length of the source_string, the original string is returned unchanged.
  • When the padding_string is longer than the remaining space to be filled, it is truncated to fit or cycled to fill the space.

Examples

1. Basic RPAD Example

SELECT RPAD('Hello', 10);

This example pads the string `'Hello'` with spaces to make it 10 characters long, resulting in `'Hello '`.

2. RPAD with Custom Padding Character

SELECT RPAD('Data', 8, '*');

Here, the string `'Data'` is right-padded with asterisks (`*`) to reach a total length of 8, resulting in `'Data****'`.

3. RPAD with Multicharacter Padding

SELECT RPAD('Align', 12, '123');

This example pads `'Align'` with the sequence `'123'` cyclically, resulting in `'Align123123'`.

Tips and Best Practices

  • Choose appropriate padding characters. Use padding characters that make sense contextually for the data presentation.
  • Consider string length. Ensure that the length argument is greater than the length of the source_string to avoid truncation.
  • Use with other functions. Combine RPAD with other string functions like LPAD for complex string formatting tasks.
  • Check character encoding. Be aware of character encoding as multibyte characters can affect the perceived length of strings.
  • Performance considerations. Be mindful of performance when using RPAD in large datasets or alongside computationally intensive operations, as excessive string manipulation can impact query performance.