I have a materialised view in my own schema which based on a table in another schema. However I want to modify the matrealise view to add a where clause which will never becomes true e.g. Where 1=2
Can i alter an existing materialised view to add this where clause in the MView query . Will alter command works or I have to drop and recreate the Mview (Which i am rluctatant to do actually)

create or replace view vw as 
  select count(*) c from hr.employees;
  
create materialized view mv as 
  select * from vw;

select * from mv;
/*
         C
----------
       107
*/

create or replace view vw as 
  select count(*) c from hr.employees
  where  1 = 2;
  
exec dbms_mview.refresh ( 'mv' );

select * from mv;
/*
         C
----------
         0
*/