How to pad a string at the left end using the LPAD() function?

LPAD(str, len, padstr) is a MySQL built-in function that truncates a string or pad it at the left end to a given length. For example:

SET @str = 'ops';

SELECT LPAD(@str, 6, 'o');
  -- +--------------------+
  -- | LPAD(@str, 6, 'o') |
  -- +--------------------+
  -- | oooops             |
  -- +--------------------+

Reference information of the LPAD() function:

LPAD(str, len, padstr): modstr
  Returns the string str, left-padded with the string padstr to a length
  of len characters. If str is longer than len, the return value is
  shortened to len characters. It returns NULL if any of its arguments
  are NULL.

Arguments, return value and availability:
  str: Required. The string that will be searched in.
  len: Required. The number of characters to be truncated or left-padded to.
  padstr: Required. The substring to pad with.
  modstr: Return value. The modified string after truncating or padding.
  Available since MySQL 4.0.

Related MySQL functions:

• RPAD() - Right-Padding String

⇒ LTRIM() - Left-Trimming String

⇐ LOWER() - Convert String to Lower Case

⇑ MySQL Functions on Character String Values

⇑⇑ MySQL Function References