Search notes:

ORA-40490: COLUMNS clause required

Not good: the following statement throws the error message ORA-40490: COLUMNS clause required:json_table needs the column clause to specify the names and datatypes of the returned columns.

select
   *
from
   json_table('[1,1,2,3,5,8,13,21]');

Better:

select
   *
from
   json_table('[1,1,2,3,5,8,13,21]', '$[*]' COLUMNS (
      num number(2)  path '$[*]'
   ))
;

ORA-40490: COLUMNS clause required

See also