Search notes:
ORA-54004: resultant data type of virtual column is not supported
If the expression evaluates to a LOB, LONG, REF or BFILE, Oracle throws ORA-54004: resultant data type of virtual column is not supported.
create table tq84_hash_test (
a number(5,2),
b date,
c varchar2(4000),
--
j as ( json_object(key 'a' value a, key 'c' value c RETURNING CLOB) )
);