Oracle NULL value also filtering -


im trying filter category 'student'. null category filtering out. please let me know how filter student not null value.

query:  select * customer category != 'student'

null isn't comporable anything, itself. include need have separate condition it:

select * customer category null or category != 'student'

you nvl or coalesce column magic value, explicitly looking null cleaner, find.

quick sql fiddle.


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