>:) Read the original message (the very first one) again.

This is the original message as is:

"Hi,

I am trying to count unique values in the field (using SQL Select) if the value is greater than 0

So, here is syntax I use (simplified) (which generates an error):
select count( case when mytable.myfield = 0 then 0 else distinct( mytable.myfield ) end ) as TotCount
What is wrong in the above syntax?

Thanks in advance"

Thus the answer is:

select count(distinct mytable.myfield) as totCount from myTable where myTable.myfield <> 0

No need for case complexity.

Anyway, your question didn't in fact have relation to original question.