COALESCE() or NVL()

Hi all,

I'm looking for a function like COALESCE() or the Oracle NVL(),
to returns a ZERO value instead of a NULL value.
To have the result: NULL+1 = 1 instead of NULL+1 = NULL
Have PostgreSQL something like this ?
I tried to write it on C but I can't realize the beavior of NULLs,
I can't get that my program returns a zero instead of a null.
I'm not a C programmer, could somebody help me ?

SELECT * FROM emp;
name       |salary|age|dept
-----------+------+---+-----
Sam        |  1200| 16|toy
Claire     |  5000| 32|shoe
Bill       |  4200| 36|shoe
Ginger     |  4800| 30|candy
NULL VALUES|      |   |
(5 rows)

SELECT name,NVL(salary)+100 AS dream FROM emp;
name       |dream
-----------+-----
Sam        | 1300
Claire     | 5100
Bill       | 4300
Ginger     | 4900
NULL VALUES|              <--- I expected 100 here.
(5 rows)
                                                Thanks, Jose'
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