MySQLi - Regexps


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You have seen MySQLi pattern matching with LIKE ...%. MySQLi supports another type of pattern matching operation based on regular expressions and the REGEXP operator. If you are aware of PHP or PERL, then it's very simple for you to understand because this matching is very similar to those scripting regular expressions.

Following is the table of pattern, which can be used along with REGEXP operator.

Pattern What the pattern matches
^ Beginning of string
$ End of string
. Any single character
[...] Any character listed between the square brackets
[^...] Any character not listed between the square brackets
p1|p2|p3 Alternation; matches any of the patterns p1, p2, or p3
* Zero or more instances of preceding element
+ One or more instances of preceding element
{n} n instances of preceding element
{m,n} m through n instances of preceding element

Examples

Now based on above table, you can device various type of SQL queries to meet your requirements. Here, I'm listing few for your understanding. Consider we have a table called tutorials_inf and it's having a field called name −

Query to find all the names starting with 'sa'

mysql>  SELECT * FROM tutorials_inf WHERE name REGEXP '^sa';

The sample output should be like this −

+----+------+
| id | name |
+----+------+
|  1 | sai  |
+----+------+
1 row in set (0.00 sec)

Query to find all the names ending with 'ai'

mysql> SELECT * FROM tutorials_inf WHERE name REGEXP 'ai$';

The sample output should be like this −

+----+------+
| id | name |
+----+------+
|  1 | sai  |
+----+------+
1 row in set (0.00 sec)

Query to find all the names, which contain 'a'

mysql> SELECT * FROM tutorials_inf WHERE name REGEXP 'a';

The sample output should be like this −

+----+-------+
| id | name  |
+----+-------+
|  1 | sai   |
|  3 | ram   |
|  4 | johar |
+----+-------+
3 rows in set (0.00 sec)

Query to find all the names starting with a vowel

mysql>  SELECT * FROM tutorials_inf WHERE name REGEXP '^[aeiou]';


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