SUBSTR[ING]

Purpose

This function returns a substring of the length length from the position position, out of the string string.

Syntax

substring::=

Usage notes

  • If length is not specified, all of the characters to the end of the string are used.

  • If position is negative, counting begins at the end of the string.

  • If position is 0 or 1, the result begins from the first character of the string.

  • If position is before the start or after the end of the string, the result is NULL.

  • For additional information, refer to the functions RIGHT, LEFT, and REGEXP_SUBSTR.

  • MID is an alias for this function.

Example

SELECT SUBSTR('abcdef',2,3) S1,
       SUBSTRING('abcdef' FROM 4 FOR 2) S2,
       SUBSTR('abcdef',-3) S3,
       SUBSTR('abcdef',7) S4,
       SUBSTR('abcdef',-7) S5
       ;
Result:

S1

S2

S3

S4

S5

bcd

de

def

NULL

NULL