drop table if exists t1; drop table if exists t2; create table t1 (p int not null primary key, u int not null, o int not null, unique (u), key(o)) engine=ndb; create table t2 (p int not null primary key, u int not null, o int not null, unique (u), key(o)) engine=ndb; insert into t1 values (1,1,1),(2,2,2),(3,3,3); insert into t2 values (1,1,1),(2,2,2),(3,3,3), (4,4,4), (5,5,5); explain select * from t2 where p NOT IN (select p from t1); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 5 Using where 2 DEPENDENT SUBQUERY t1 unique_subquery PRIMARY PRIMARY 4 func 1 select * from t2 where p NOT IN (select p from t1) order by p; p u o 4 4 4 5 5 5 explain select * from t2 where p NOT IN (select u from t1); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 5 Using where 2 DEPENDENT SUBQUERY t1 unique_subquery u u 4 func 1 select * from t2 where p NOT IN (select u from t1) order by p; p u o 4 4 4 5 5 5 explain select * from t2 where p NOT IN (select o from t1); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 5 Using where 2 DEPENDENT SUBQUERY t1 index_subquery o o 4 func 1 select * from t2 where p NOT IN (select o from t1) order by p; p u o 4 4 4 5 5 5 explain select * from t2 where p NOT IN (select p+0 from t1); id select_type table type possible_keys key key_len ref rows Extra 1 PRIMARY t2 ALL NULL NULL NULL NULL 5 Using where 2 DEPENDENT SUBQUERY t1 ALL NULL NULL NULL NULL 3 Using where select * from t2 where p NOT IN (select p+0 from t1) order by p; p u o 4 4 4 5 5 5 drop table t1; drop table t2; create table t1 (p int not null primary key, u int not null) engine=ndb; insert into t1 values (1,1),(2,2),(3,3); create table t2 as select t1.* from t1 as t1, t1 as t2, t1 as t3, t1 as t4, t1 as t5, t1 as t6, t1 as t7, t1 as t8 where t1.u = t2.u and t2.u = t3.u and t3.u = t4.u and t4.u = t5.u and t5.u = t6.u and t6.u = t7.u and t7.u = t8.u; select * from t2 order by 1; p u 1 1 2 2 3 3 drop table t1; drop table t2;