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NULLIF
Syntax
Compatibility
ODBC compatible
NULLIF
Returns a NULL value for expression1 if it is equal to expression2. It is useful for converting
values to NULL from applications that use some other representation for missing or unknown
data. The NULLIF scalar function is a type of conditional expression.
Example This example uses the NULLIF scalar function to insert a NULL value into an address column if
the host-language variable contains a single space character:
Notes • This function is not allowed in a GROUP BY clause.
NVL
Syntax
NULLIF ( expression1, expression2 )
INSERT INTO employee (add1) VALUES (NULLIF (:address1, ' '));
• Arguments to this function cannot be query expressions.
• The NULLIF expression is shorthand notation for a common case that can also be
represented in a CASE expression, as shown:
CASE
WHEN expression1 = expression2 THEN NULL
ELSE expression1
END
Compatibility
SQL compatible
Returns the value of the first expression if the first expression value is not NULL. If the first
expression value is NULL, the value of the second expression is returned.
NVL ( expression , expression )
Example This example illustrates the NVL function:
SELECT salary + NVL (comm, 0) 'TOTAL SALARY' FROM employee ;
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