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regexp_like

1. REGEXP_LIKE Function​

The REGEXP_LIKE function in H2 database is used to check if a given string matches a specified regular expression pattern.

2. Syntax​

The syntax for the REGEXP_LIKE function in H2 database is as follows:

REGEXP_LIKE(input_string, regex_pattern)

Arguments​

  • input_string: The string value that needs to be checked against the regular expression pattern.
  • regex_pattern: The regular expression pattern that the input string is matched against.

Return​

  • The REGEXP_LIKE function returns a boolean value: TRUE if the input string matches the provided regular expression pattern, and FALSE otherwise.

3. Notes​

  • The REGEXP_LIKE function in H2 database follows the Java regular expression syntax.
  • The regular expression pattern can contain a combination of characters and special metacharacters to define the pattern matching rules.
  • If the input string is NULL or the regular expression pattern is empty, the REGEXP_LIKE function will return NULL.
  • Take caution while constructing regular expressions, as incorrect patterns may lead to unexpected results or errors.

4. Examples​

Here are a few examples demonstrating the usage of the REGEXP_LIKE function in H2 database:

Example 1 - Checking if a string matches a pattern:​

SELECT REGEXP_LIKE('Hello World', '^Hello.*') AS is_match;

Output:

is_match
--------
TRUE

Example 2 - Using a case-insensitive regular expression:​

SELECT REGEXP_LIKE('Database', 'database', 'i') AS is_match;

Output:

is_match
--------
TRUE

Example 3 - Checking multiple strings against a pattern:​

SELECT name
FROM users
WHERE REGEXP_LIKE(name, '^[A-Za-z]+$');

Output:

name
-----
John
Alice
  • regexp_replace - Replace matched substrings using a regular expression.
  • REGEXP_INSTR - Find the position of a substring matching a regular expression.