Найдите названия всех кораблей из базы данных, спущенных на воду до 1941 г.

select name from ships where launched<1941
union
select ship from outcomes inner join battles on battle=name
where year(date)<1941

union
select o.ship
from outcomes o inner join classes cl on o.ship=cl.class
where (select min(launched) from ships where class=o.ship)<1941

union
select o.ship from outcomes o
inner join classes cl on o.ship=cl.class where
(select min(year(bb.date)) from outcomes oo join battles bb on oo.battle=bb.name
where oo.ship in(select name from ships where class=o.ship))<1941

union
select o.ship from outcomes o
left join classes cl on o.ship=cl.class
left join battles on battle=name where year(date)<1941
and not exists (select name from ships where name<>o.ship and class<>o.ship)

union
select name from ships where launched is null
and class in (
select class from ships where launched<1941
union
select o.ship from outcomes o
inner join battles on o.battle=battles.name
where year(date)<1941
union
select o.ship from outcomes o
inner join classes cl on o.ship=cl.class where
(select min(year(bb.date)) from outcomes oo join battles bb on oo.battle=bb.name
where oo.ship in(select name from ships where class=o.ship))<1941
)

пишет несоответствие данных 24... Если убрать последний юнион, то пишет что не хватает еще одного корабля. Пожалыйста помогите!!! если можно скиньте решение на мыло.