Division by zero problem

I've got the following SQL

SELECT count(*) FROM tablea A
JOIN tableb B ON ..etc..
WHERE a.string_val = 'test' AND
b.divider 0 AND
a.number 0 AND
(a.number / b.divider 0)

The b.divider value can be 0, but still I get the division by zero
error message.
I guess the reason is that the database performs the where statements
one at the time?

So when performing the division a.number / b.divider it could get 0 in
the divider even if b.divider 0 is also part of the where
statement??

My question is then.. How can I work around this problem? Changing the
database to set b.divider always 0 is not an optionMaybe this?

SELECT count(*) FROM tablea A
JOIN tableb B ON ..etc..
WHERE a.string_val = 'test' AND
b.divider 0 AND
a.number 0 AND
(a.number / NULLIF(b.divider,0) 0)|||Thank you :)