New features in Mysql 5.1

Partitions:
mysql> CREATE TABLE part_tab
-> ( c1 int default NULL,
-> c2 varchar(30) default NULL,
-> c3 date default NULL
->
-> ) engine=myisam
-> PARTITION BY RANGE (year(c3)) (PARTITION p0 VALUES LESS THAN (1995),
-> PARTITION p1 VALUES LESS THAN (1996) , PARTITION p2 VALUES LESS THAN (1997) ,
-> PARTITION p3 VALUES LESS THAN (1998) , PARTITION p4 VALUES LESS THAN (1999) ,
-> PARTITION p5 VALUES LESS THAN (2000) , PARTITION p6 VALUES LESS THAN (2001) ,
-> PARTITION p7 VALUES LESS THAN (2002) , PARTITION p8 VALUES LESS THAN (2003) ,
-> PARTITION p9 VALUES LESS THAN (2004) , PARTITION p10 VALUES LESS THAN (2010),
-> PARTITION p11 VALUES LESS THAN MAXVALUE );
Query OK, 0 rows affected (0.00 sec)

XPath functions:
EXTRACTVALUE, UPDATEXML

SELECT EXTRACTVALUE(doc,'/book/author/initial') FROM x;
SELECT
UpdateXML('ccc', '/a', 'fff') AS val1,
UpdateXML('ccc', '/b', 'fff') AS val2,
UpdateXML('ccc', '//b', 'fff') AS val3,
UpdateXML('ccc', '/a/d', 'fff') AS val4,
UpdateXML('ccc', '/a/d', 'fff') AS val5
-> \G

From: http://www.mysql.com/why-mysql/white-papers/whatsnew-mysql-51.pdf