REGEXP_SUBSTR

The REGEXP_SUBSTR function searches a string for a substring of a specified pattern and returns that substring.

Return Value

VARCHAR2 | CLOB

Syntax

REGEXP_SUBSTR(source_char, pattern[, position[, occurrence[, match_parameter ]]])

Parameters

source_char

The text expression for which the function searches.

pattern

The text expression for which the function searches. It is usually a text literal and can contain up to 512 bytes. The function interprets a period as a wildcard character that matches any character

position

A positive integer that indicates the character of source_char at which the function begins the search. The default value of position is 1, which means that the function begins searching at the first character of source_char.

occurrence

A positive integer that indicates which occurrence of pattern the function should search for. The default value of occurrence is 1, which means that the function searches for the first occurrence of pattern.

match_parameter

A text expression that lets you change the default matching behavior of the function. You can specify one or more of the values shown in the following table.

Value	Specifies
`c`	Case-sensitive matching.
`i`	Case-insensitive matching.
`m`	Treat the source string as multiple lines. The function interprets `^` (caret) and `$` (dollar sign) as the start and end, respectively, of any line anywhere in the source string, rather than only at the start or end of the entire source string. By default, the function treats the source string as a single line.
`n`	A newline character is among the characters matched by a period (the wildcard character). By default, it is not.
`x`	Ignores whitespace characters.

Examples

Example 8-67 Using REGEXP_SUBSTRING to search for a case-insensitive substring

The following statement

REGEXP_SUBSTR('7 W 96th St, New York, New York', 'new york', 10, 2, 'i')

starts searching at the tenth character and matches the second instance of New York in a case-insensitive match.

Example 8-68 Using REGEXP_SUBSTRING to return a substring from a string enclosed in single quotes

The following statement

REGEXP_SUBSTR('parsley, sage, rosemary, thyme', ',[^,]+,', 1)

matches the first substring enclosed in single quotes ('), and returns the value, sage,.