SELECT * FROM tour LEFT JOIN boat on tour.boatID = boat.boatID
LEFT JOIN boat_ru ON boat_ru.boatID = boat.boatID
LEFT JOIN country on tour.countryID = country.countryID
LEFT JOIN country_ru ON country_ru.countryID = country.countryID
LEFT JOIN itinerary on tour.itineraryID = itinerary.itineraryID
LEFT JOIN itinerary_ru ON itinerary_ru.itineraryID = itinerary.itineraryID WHERE tour.tourID = tours;
Неправильный запрос