create table PERSON ( 
    PERSON_KEY number(19),  
    FNAME varchar2(20 char),  
    LNAME varchar2(20 char)  
    )

insert into PERSON  
select '1','Jeremy','Mallard' from dual union 
select '2','Marilyn','Foster' from dual

commit

create or replace type String4000List as table of varchar2(4000); 

declare  
    vPersonList String4000List;  
    vMallard number;  
 
begin 
    vPersonList := String4000List();  
     
    select json_object (  
        'PERSON_KEY' value p.PERSON_KEY,  
        'FNAME' value min(p.FNAME),  
        'LNAME' value min(p.LNAME)  
        ) PERSON  
        bulk collect into vPersonList  
    from PERSON p 
    group by p.PERSON_KEY;  
     
    for i in ( 
        select column_value  
        from table(vPersonList)  
        ) 
    loop  
        DBMS_OUTPUT.put_line (i.column_value);  
    end loop i;  
     
    select count(*)  
        into vMallard  
    from table(vPersonList) pl  
--        where pl.column_value.LNAME = 'Mallard';  
        where pl.column_value like '%Mallard%';  
 
    DBMS_OUTPUT.put_line (vMallard);  
end;