SELECT `employees`.*, `titles`.`title`, `salaries`.`salary`
FROM `employees`
LEFT JOIN `titles` ON
(`titles`.`emp_no` = `employees`.`emp_no`) AND
(`titles`.`from_date` = (SELECT MAX(`from_date`) FROM `titles` WHERE `titles`.`emp_no` = `employees`.`emp_no`))
LEFT JOIN `salaries` ON
(`salaries`.`emp_no` = `employees`.`emp_no`) AND
(`salaries`.`from_date` = (SELECT MAX(`from_date`) FROM `salaries` WHERE `salaries`.`emp_no` = `employees`.`emp_no`))
WHERE (`titles`.`title`='Staff') AND (`salaries`.`salary`>='120000')
LIMIT 0, 20
a topic indító :)