NVL

Syntax

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Purpose

NVL lets you replace null (returned as a blank) with a string in the results of a query. 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 data type. If their data types are different, then Oracle Database implicitly converts one to the other. If they cannot be converted implicitly, then the database returns an error. The implicit conversion is implemented as follows:

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

• If expr1 is numeric, then Oracle Database determines which argument has the highest numeric precedence, implicitly converts the other argument to that data type, and returns that data type.

  See Also:

  • Table 2-10, "Implicit Type Conversion Matrix" for more information on implicit conversion and "Numeric Precedence" for information on numeric precedence

  • "COALESCE" and "CASE Expressions", which provide functionality similar to that of NVL

Examples

The following example returns a list of employee names and commissions, substituting "Not Applicable" if the employee receives no commission:

SELECT last_name, NVL(TO_CHAR(commission_pct), 'Not Applicable') commission
 FROM employees
 WHERE last_name LIKE 'B%'
 ORDER BY last_name;
 
LAST_NAME COMMISSION
------------------------- ----------------------------------------
Baer Not Applicable
Baida Not Applicable
Banda .1
Bates .15
Bell Not Applicable
Bernstein .25
Bissot Not Applicable
Bloom .2
Bull Not Applicable