![STUFF function [String]](arrow-left.gif){kind=icon}
![SUM function [Aggregate]](arrow-right.gif){kind=icon}
Returns a substring of a string.
{ SUBSTRING | SUBSTR } ( string-expression, start [ , length ] )
string-expression The string from which a substring is to be returned.
start The start position of the substring to return, in characters. A negative starting position specifies a number of characters from the end of the string instead of the beginning. The first character in the string is at position 1.
length The length of the substring to return, in characters. A positive length specifies that the substring ends length characters to the right of the starting position, while a negative length specifies that the substring ends length characters to the left of the starting position.
The following statement returns “back”:
SELECT SUBSTRING ( 'back yard', 1 , 4 ) FROM iq_dummy
The following statement returns yard:
SELECT SUBSTR ( 'back yard', -1 , -4 ) FROM iq_dummy
The following statement returns 0x2233:
SELECT SUBSTR ( 0x112233445566, 2, 2 ) FROM iq_dummy
If length is specified, the substring is restricted to that length. If no length is specified, the remainder of the string is returned, starting at the start position.
Both start and length can be negative. Using appropriate combinations of negative and positive numbers, you can get a substring from either the beginning or end of the string.
