1. create table@H_502_3@

postgres=# create table tb5 (id integer,age integer);
CREATE TABLE

postgres=# \d tb5
      Table "public.tb5"
 Column |  Type   | Modifiers 
--------+---------+-----------
 id     | integer | 
 age    | integer | 

postgres=# insert into tb5 select generate_series(1,10),random()*10::integer;
INSERT 0 10

postgres=# select * from tb5;
 id | age 
----+-----
  1 |   6
  2 |   2
  3 |   1
  4 |   7
  5 |   8
  6 |   9
  7 |   0
  8 |   6
  9 |  10
 10 |   0
(10 rows)

postgres=# select * from tb5 where age=1 or age=2 or age=7;
 id | age 
----+-----
  2 |   2
  3 |   1
  4 |   7
(3 rows)

postgres=# explain analyze select * from tb5 where age=1 or age=2 or age=7;
                                          QUERY PLAN                                           
-----------------------------------------------------------------------------------------------
 Seq Scan on tb5  (cost=0.00..85.25 rows=64 width=8) (actual time=0.008..0.010 rows=3 loops=1)
   Filter: ((age = 1) OR (age = 2) OR (age = 7))
   Rows Removed by Filter: 7
 Total runtime: 0.024 ms
(4 rows)

postgres=# select * from tb5 where age in(1,2,7);
 id | age 
----+-----
  2 |   2
  3 |   1
  4 |   7
(3 rows)

postgres=# explain analyze select * from tb5 where age in(1,7);
                                          QUERY PLAN                                           
-----------------------------------------------------------------------------------------------
 Seq Scan on tb5  (cost=0.00..69.12 rows=64 width=8) (actual time=0.007..0.008 rows=3 loops=1)
   Filter: (age = ANY ('{1,7}'::integer[]))
   Rows Removed by Filter: 7
 Total runtime: 0.020 ms
(4 rows)

note: the 'OR' operation in explain be changed the 'ANY' operation,It can be seen that postgresql handle the 'OR' operation by 'ANY' operation。@H_502_3@ 5. test 'ANY'

postgres=# select * from tb5 where age=ANY('{1,7}');
 id | age 
----+-----
  2 |   2
  3 |   1
  4 |   7
(3 rows)

postgres=# explain analyze select * from tb5 where age=ANY('{1,7}');
                                          QUERY PLAN                                           
-----------------------------------------------------------------------------------------------
 Seq Scan on tb5  (cost=0.00..69.12 rows=64 width=8) (actual time=0.008..0.009 rows=3 loops=1)
   Filter: (age = ANY ('{1,7}'::integer[]))
   Rows Removed by Filter: 7
 Total runtime: 0.020 ms
(4 rows)

@H_502_3@

ConClusion: The IN operation can be change the OR operation,and the OR operation can be changed the ANY operation. So,when we use the IN or OR operaion,@H_502_3@

we can use ANY instead of them.@H_502_3@