Oracle DB: NVL Function

DESCRIPTION

NVL replaces NULL value with other value in the results of a query.

SYNTAX

NVL(expr1, expr2)

PARAMETERS or ARGUMENTS

If expr1 is NULL, then NVL returns expr2. If expr1 is not NULL, then NVL returns expr1.

The arguments expr1 and expr2 can have any datatype. If their datatypes are different, then Oracle Database implicitly converts one to the other. If they are cannot be converted implicitly, the database returns an error.

The implicit conversion is implemented as follows:

-          If expr1 is character data, then Oracle Database converts expr2 to the datatype of expr1 before comparing them and returns VARCHAR2 in the character set of expr1.

-          If expr1 is numeric, then Oracle determines which argument has the highest numeric precedence, implicitly converts the other argument to that datatype, and returns that datatype.

EXAMPLES

SQL> SELECT NVL(supplier_city, 'n/a')

       FROM suppliers;

The SQL statement above would return 'n/a' if the supplier_city field contained a NULLvalue. Otherwise, it would return the supplier_city value.