Performance wise which is better NOT IN or NOT EXISTS

Performance wise which is better NOT IN or NOT EXISTS.

also that not exists is not equivalent to not in
SQL> select * from dept where not exists (select * from emp where dept.deptno=comm);
    DEPTNO DNAME          LOC
        10 ACCOUNTING     NEW YORK
        20 RESEARCH       DALLAS
        30 SALES          CHICAGO
        40 OPERATIONS     BOSTON
SQL> select * from dept where deptno not in (select comm from emp);
no rows selectedin most case, Oracle internally rewrite a NOT IN in a NOT EXISTS, because NOT EXISTS usually performs better.
HTH
Laurent

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