Oracle/PLSQL: SUBSTR Function
This Oracle tutorial explains how to use the Oracle/PLSQL SUBSTR function with syntax and examples.
Description
The Oracle/PLSQL SUBSTR functions allows you to extract a substring from a string.
Syntax
The syntax for the SUBSTR function in Oracle/PLSQL is:
SUBSTR( string, start_position [, length ] )
Parameters or Arguments
- string
- The source string.
- start_position
- The starting position for extraction. The first position in the string is always 1.
- length
- Optional. It is the number of characters to extract. If this parameter is omitted, the SUBSTR function will return the entire string.
Note:
- If start_position is 0, then the SUBSTR function treats start_position as 1 (ie: the first position in the string).
- If start_position is a positive number, then the SUBSTR function starts from the beginning of the string.
- If start_position is a negative number, then the SUBSTR function starts from the end of the string and counts backwards.
- If length is a negative number, then the SUBSTR function will return a NULL value.
- See also the REGEXP_SUBSTR function.
Applies To
The SUBSTR function can be used in the following versions of Oracle/PLSQL:
- Oracle 12c, Oracle 11g, Oracle 10g, Oracle 9i, Oracle 8i
Example
Let's look at some Oracle SUBSTR function examples and explore how to use the SUBSTR function in Oracle/PLSQL.
For example:
SUBSTR('This is a test', 6, 2)
Result: 'is'
SUBSTR('This is a test', 6)
Result: 'is a test'
SUBSTR('TechOnTheNet', 1, 4)
Result: 'Tech'
SUBSTR('TechOnTheNet', -3, 3)
Result: 'Net'
SUBSTR('TechOnTheNet', -6, 3)
Result: 'The'
SUBSTR('TechOnTheNet', -8, 2)
Result: 'On'