How to make null equal null in oracle

Question

I have a variable being passed to my stored proc and it's a filter (basically). However, that field can sometimes be null, and if it is, I want to be able to check against the rows that have that field as null.

For example,

Table A:

VALUE_COLUMN | FILTER_COLUMN
----------------------------
A            |  (NULL)
B            |  (NULL)           
C            |  (NULL)
D            |  (NULL)
A            |  1
E            |  (NULL)
F            |  (NULL)
B            |  1

The query (With inputs, val, filter):

SELECT  COUNT(1)
  FROM    TableA
WHERE 
  wrap_up_cd = val
  AND brn_brand_id = filter

Expected I/O:

val = A, filter = (null) = 1
val = A, filter = 1 = 1
val = C, filter = 1 = 0

How can I make Oracle behave this way?

Answer 1

How about:

SELECT  COUNT(1)
  FROM    TableA
WHERE 
  wrap_up_cd = val
  AND ((brn_brand_id = filter) OR (brn_brand_id IS NULL AND filter IS NULL))

I'm not an Oracle expert, but I'd expect that to work - basically make the query match if both the filter and the value are NULL.

Answer 2

Oracle doesn't have an ISNULL function. So you'd need something like

SELECT COUNT(*)
  FROM tableA
 WHERE brn_brand_id = filter
    OR (    brn_brand_id IS NULL 
        AND filter IS NULL)