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 Using index 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 Using index 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 Using index 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;