REGEXP_LIKE(source_string, pattern [, match_parameter ])
 
-- examples:
 
-- Select domains that contain 2 and only 2 letters:
SELECT *
FROM domains
WHERE regexp_like (key, '^[a-z]{2}$');
 
 
-- The following query returns the first and last names for 
-- those employees with a first name of Steven or Stephen 
- (WHERE first_name begins WITH 'Ste' AND ends WITH 'en' AND IN 
-- between is either 'v' or 'ph'):
 
SELECT first_name, last_name
FROM employee_table
WHERE REGEXP_LIKE (first_name, '^Ste(v|ph)en$');
 
 
-- This query returns the last name for employees with a 
-- double vowel in their last name (where last_name contains 
-- two adjacent occurrences of either a, e, i, o, or u, 
-- regardless of case):
 
SELECT last_name
FROM employee_table
WHERE REGEXP_LIKE (last_name, '([aeiou])\1', 'i');
 
LAST_NAME
-------------------------
De Maab
Greenberg
Soo
Green
Greene
Klopp
 
 
-- search for valid email addresses:
SELECT page_content 
FROM test_list
WHERE REGEXP_LIKE (page_content, '[A-Z0-9._%-]+@[A-Z0-9._%-]+\.[A-Z]{2,4}');
 
 
-- search only for '.com' email addresses:
 
SELECT email 
FROM email_list 
WHERE REGEXP_LIKE (email, '[A-Z0-9._%-]+@[A-Z0-9._%-]+\.com');