Question about Performance Operators

Question

Hello friends...
I have a doubt, can anyone help me?
whats the bes operator for good performance ?
select...
from...
where ID IN (a,b)
or
select...
from...
where ID =a or id=b
Tks

Answer 1

In terms of how Oracle uses them, they are they are essentially the same. With an explicit list like your example, Oracle will generally internally re-write the IN to a series of ORs.
I would use IN in almost all cases since it is more readable and easier to get right if you have other predicates. For example:
SQL> SELECT * FROM t;
        ID DESCR
         1 One
         1 Un
         2 One
         2 Deux
         3 One
SQL> SELECT * FROM t
  2  WHERE id in (1, 2) and
  3        descr = 'One';
        ID DESCR
         1 One
         2 One
SQL> SELECT * FROM t
  2  WHERE id = 1 or
  3        id = 2 and
  4        descr = 'One';
        ID DESCR
         1 One
         1 Un
         2 One
SQL> SELECT * FROM t
  2  WHERE (id = 1 or
  3         id = 2) and
  4        descr = 'One';
        ID DESCR
         1 One
         2 OneJohn