SQL Reference Guide

SUBSTR function (extension)

Syntax

SUBSTR ( char_expression, start_position [, length ] )

Description

The scalar function SUBSTR returns the substring of the character string corresponding to the first argument starting at start_position and length characters long. If the third argument length is not specified, substring starting at start_position up to the end of char_expression is returned.

Example

SELECT name, '(', SUBSTR (phone, 1, 3) , ')',

SUBSTR (phone, 4, 3), '-',

SUBSTR (phone, 7, 4)

FROM customer ;

Notes

• The first argument must be of character type.
• The second argument must be of type INTEGER.
• The third argument, if specified, must be of type INTEGER.
• The values for specifying position in the character string start from one. The very first character in a string is at position one, the second character is at position two and so on.
• The result is of character type.
• If any of the argument expressions evaluates to null, the result is null.