Search notes:

ORA-02438: Column check constraint cannot reference other columns

create table tq84_ora_02438 (
   a  number,
   b  number  check ( a+b > 42 )
);

Better:

create table tq84_ora_02438 (
   a  number,
   b  number,
   --
   check ( a+b > 42 )
);

Typos

This error is also thrown when a non-existing column is specified in the check constraint, for example because of a typO:

create table tq84_ora_02438 (
  col_one    number(1) not null check (col_one   between 1 and 5),
  col_two    number(1) not null check (col_tow   between 3 and 7), -- Note the typo (col_tow)
  col_three  number(1) not null check (col_three between 2 and 8)
);

See also

Check constraints

Other Oracle error messages