REGEXP_MATCH()

Warning

SingleStore 9.0 gives you the opportunity to preview, evaluate, and provide feedback on new and upcoming features prior to their general availability. In the interim, SingleStore 8.9 is recommended for production workloads, which can later be upgraded to SingleStore 9.0.

Syntax

REGEXP_MATCH (<source_string>, <pattern> [, <parameters> ] ] )

Arguments

source_string: The string from which to extract substrings that match a regular expression.
pattern: A string representing a regular expression.
parameters:An optional argument, if present, has one of the following values:
- c: Perform case-sensitive matching.
- i: Perform case-insensitive matching.
- If c or i is not specified, performs case-sensitive matching.

Remarks

If no match is found, the REGEXP_MATCH result will be NULL.
If a match is found, and the pattern does not contain parenthesized sub-expressions, the result is a single-element text array containing the substring that matches the entire pattern. This result is similar to the REGEXP_SUBSTR() function.
If a match is found, and the pattern contains parenthesized sub-expressions, the result is a JSON array of strings, whose n'th element is the substring matching the n'th parenthesized sub-expression of the pattern (not counting "non-capturing" parentheses). See the examples section for more details.

Examples

The following examples demonstrate how REGEXP_MATCH works when the global variable REGEXP_FORMAT is set to advanced.

SQL

SET GLOBAL REGEXP_FORMAT = 'advanced';

Searches for a group of characters between the alpha and gamma in the substrings.

SQL

SELECT REGEXP_MATCH('alphabetagammadelta', 'alpha(.*)gamma');

+-------------------------------------------------------+
| REGEXP_MATCH('alphabetagammadelta', 'alpha(.*)gamma') |
+-------------------------------------------------------+
| ["beta"]                                              |
+-------------------------------------------------------+

Searches for a group of digits, which occurs after the word gamma.

SQL

SELECT REGEXP_MATCH('alphabetagamma579XYZ', 'gamma([0-9]+)');

+-------------------------------------------------------+
| REGEXP_MATCH('alphabetagamma579XYZ', 'gamma([0-9]+)') |
+-------------------------------------------------------+
| ["579"]                                               |
+-------------------------------------------------------+

There is no capturing group (i.e., parenthesized subexpressions), so the returned values matches the entire substring pattern.

SQL

SELECT REGEXP_MATCH('alphabetagammadelta', 'alpha.*gamma');

+-----------------------------------------------------+
| REGEXP_MATCH('alphabetagammadelta', 'alpha.*gamma') |
+-----------------------------------------------------+
| ["alphabetagamma"]                                  |
+-----------------------------------------------------+

This example matches data based on the each part of the date (i.e., by month, day, and year). It will also accept invalid dates (e.g., 29-11-000).

To use \d expression inside the pattern, the regexp_format global variable should be set to advanced. Also, when using SingleStore strings an escape should be used.

SQL

SELECT REGEXP_MATCH('04-08-2023', '(\\d{2})-(\\d{2})-(\\d{4})');

+----------------------------------------------------------+
| REGEXP_MATCH('04-08-2023', '(\\d{2})-(\\d{2})-(\\d{4})') |
+----------------------------------------------------------+
| ["04","08","2023"]                                       |
+----------------------------------------------------------+

Returns the first occurrences of a group of lowercase characters followed by groups of digits.

SQL

SELECT REGEXP_MATCH('abc357cde123abc', '[a-z]+([0-9]+)');

+---------------------------------------------------+
| REGEXP_MATCH('abc357cde123abc', '[a-z]+([0-9]+)') |
+---------------------------------------------------+
| ["357"]                                           |
+---------------------------------------------------+

Returns NULL since there is no match.

SQL

SELECT REGEXP_MATCH('alphabetagammadelta', 'alpha(.*)eplison');

+---------------------------------------------------------+
| REGEXP_MATCH('alphabetagammadelta', 'alpha(.*)eplison') |
+---------------------------------------------------------+
| NULL                                                    |
+---------------------------------------------------------+

This is a case-sensitive search.

SQL

SELECT REGEXP_MATCH('ALPHAbetagammadelta', 'alpha(.*)gamma', 'c');

+------------------------------------------------------------+
| REGEXP_MATCH('ALPHAbetagammadelta', 'alpha(.*)gamma', 'c') |
+------------------------------------------------------------+
| NULL                                                       |
+------------------------------------------------------------+

This is a case-sensitive search.

SQL

SELECT REGEXP_MATCH('ALPHAbetagammadelta', 'alpha(.*)gamma', 'i');

+------------------------------------------------------------+
| REGEXP_MATCH('ALPHAbetagammadelta', 'alpha(.*)gamma', 'i') |
+------------------------------------------------------------+
| ["beta"]                                                   |
+------------------------------------------------------------+

The first group is non-capturing (?:) but needs to be matched.

SQL

SELECT REGEXP_MATCH('barbeta', '(?:ba.)(beta)');

+------------------------------------------+
| REGEXP_MATCH('barbeta', '(?:ba.)(beta)') |
+------------------------------------------+
| ["beta"]                                 |
+------------------------------------------+

The second group is optional if it was not captured. JSON null will be present in the output array.

SQL

SELECT REGEXP_MATCH('alphabarbeta', '(bar)(.+)?(beta)');

+--------------------------------------------------+
| REGEXP_MATCH('alphabarbeta', '(bar)(.+)?(beta)') |
+--------------------------------------------------+
| ["bar",null,"beta"]                              |
+--------------------------------------------------+

The '?=' expression is used for a positive lookahead; it is not a captured group.

SQL

SELECT REGEXP_MATCH('barbeta', '(bar)(?=beta)');

+------------------------------------------+
| REGEXP_MATCH('barbeta', '(bar)(?=beta)') |
+------------------------------------------+
| ["bar"]                                  |
+------------------------------------------+

Extracting a Matched Group From a JSON Array in a Table

The REGEXP_MATCH builtin returns a JSON array of matches. Sometimes, you may need to obtain the exact matched string (i.e., extract the element from the array); to do this, use the JSON_EXTRACT_STRING builtin or shorthand ::$ syntax.

Examples

Create a table and insert some values.

SQL

CREATE TABLE filenames(source_strings text);

INSERT INTO filenames VALUES("file_expense_record.pdf"), ("file_24082023.pdf"),("inventory_file_new.pdf.tmp");

This statement extracts the first element from the array (note there is a zero (0) indexing).

SQL

SELECT REGEXP_MATCH(source_strings, '^(file.+)\\.pdf$') AS a, JSON_EXTRACT_STRING(a, 0) AS b FROM filenames;

+-------------------------+---------------------+
| a                       | b                   |
+-------------------------+---------------------+
| ["file_expense_record"] | file_expense_record |
| NULL                    | NULL                |
| ["file_24082023"]       | file_24082023       |
+-------------------------+---------------------+

This statement also extracts the first element but uses the shorthand format.

SQL

SELECT REGEXP_MATCH(source_strings, '^(file.+)\\.pdf$') rmatch, rmatch::$`0` FROM filenames;

+-------------------------+---------------------+
| rmatch                  | rmatch::$`0`        |
+-------------------------+---------------------+
| ["file_expense_record"] | file_expense_record |
| NULL                    | NULL                |
| ["file_24082023"]       | file_24082023       |
+-------------------------+---------------------+

REGEXP_MATCH()

On this page

Syntax

Arguments

Remarks

Examples

Extracting a Matched Group From a JSON Array in a Table

Examples

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