Useful link for type Casting in MySql

Useful link for type Casting in MySql with good Example

http://jeweladmin.wordpress.com/2008/10/11/mysql-type-casting/

CAST(expression as type)

The type can be one of the following values:
BINARY[(N)]
CHAR[(N)]
DATE
DATETIME
DECIMAL[(M[,D])]
SIGNED [INTEGER]
TIME
UNSIGNED [INTEGER]

More Example :

If a field with datatype VARCHAR(100) and also have a value “0420″

For normal selection of data you got a value 0420 which is a string. But you want a integer value that is 420.

You can write a sql like 

SQL query: SELECT CAST(fld_name AS UNSIGNED INTEGER) as 

fld_name FROM tbl_name LIMIT 0,1;