VALUE(x,y,...) 

VALUE(x,y,...) is a special function that can be used to replace NULL values with a non-NULL value.

The arguments (expressions) of the VALUE function must be comparable. The expressions are evaluated one after the other in the specified order.

	Result of the VALUE(x,y,...) function
One of the arguments is a non-NULL value	The first non-NULL value that occurs
Each argument is a special NULL value	Special NULL value
Each argument is a NULL value	NULL value

Examples

SQL Tutorial, Converting Values