mysql> create table q as WITH recursive numbers AS (select 0 as id union all select id + 1 from numbers where id < 100000) select * from numbers;
Query OK, 100001 rows affected (0.43 sec)
Records: 100001  Duplicates: 0  Warnings: 0

mysql> create index q_id on q(id);
Query OK, 0 rows affected (0.37 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> create table q1 as WITH recursive numbers AS (select 0 as id union all select id + 1 from numbers where id < 1000) select * from numbers;
Query OK, 1001 rows affected (0.03 sec)
Records: 1001  Duplicates: 0  Warnings: 0

mysql> create index q1_id on q1(id);
Query OK, 0 rows affected (0.03 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> select * from q where exists (select q1.id from q1 where q.id=q1.id);
1001 rows in set (0.01 sec)

mysql> select * from q where find_in_set(q.id, (select group_concat(q1.id) from q1));
1001 rows in set (2.00 sec)

mysql> create table q2(id int(11)) ENGINE = MEMORY;
Query OK, 0 rows affected, 1 warning (0.01 sec)

mysql> set autocommit=0;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into q2(id) values (1);
Query OK, 1 row affected (0.01 sec)

mysql> drop table q2;

и здесь висим...