User Defined Functions
You can execute PHP code as a user defined function inside MySQL.

Loading the PHP UDF library
CREATE FUNCTION php RETURNS STRING SONAME 'myphp.so';
Hello World
mysql> SELECT php('hello, world!');
+---------------------------------+
| php('hello, world!')            |
+---------------------------------+
| hello, world!                   |
+---------------------------------+
1 row in set (0.36 sec)

mysql> SELECT php('strftime("%c")');
+--------------------------+
| php('strftime("%c")')    |
+--------------------------+
| Thu Oct 24 18:12:04 2002 |
+--------------------------+
1 row in set (0.36 sec)
Applying PHP on a selected column
mysql> CREATE TABLE test (s varchar(255));
mysql> insert into test values ('iguana'),('turtle'),('aardvark');
mysql> select s,php('strlen($argv[1])',s) FROM test;
+----------+---------------------------+
| s        | php('strlen($argv[1])',s) |
+----------+---------------------------+
| iguana   | 6                         |
| turtle   | 6                         |
| aardvark | 8                         |
+----------+---------------------------+
3 rows in set (1.07 sec)
Oh my!
mysql> create table code (name varchar(255), code mediumblob);
mysql> insert into code values ('capitalize','strtoupper($argv[1])');
mysql> select php(code,s) FROM test,code WHERE code.name = 'capitalize';
+-------------+
| php(code,s) |
+-------------+
| IGUANA      |
| TURTLE      |
| AARDVARK    |
+-------------+