Oracle: summing column value with subquery?

Are there some restrictions in Oracle that disallows to have a WHERE clause that compares value of column+(subquery count(*))? If the subquery table is empty, count(*) doesn’t yield to zero in this scenario.

I expect this query

select * from Foo where (x+(select count(*) from SomeEmptyTable))>0

To be identical to

select * from Foo where x>0

But instead Oracle doesn’t return any results with the first query. In MySql the both queries return the same result selt.

My test SQL snippets:

create table Foo ( x int );

insert into Foo values ( 1 );

create table SomeEmptyTable ( x int );

I’m using Oracle Database 11g Enterprise Edition Release 11.2.0.4.0

UPDATE:

Or does the comparison to zero have some special meaning in this case?

Both

select * from Foo where (x+(select count(*) from SomeEmptyTable))>=0

and

select * from Foo where (x+(select count(*) from SomeEmptyTable))>-1

Returns 1 row as would be expected. Only when compared to >0 zero rows are returned.