Prueba asi:
Código SQL:
Ver originalUPDATE Empleados
SET Salario = Salario * 1.2
FROM Empleados E
INNER JOIN (
SELECT NumeroEmpleado, COUNT(1) TotalHabit
FROM Limpieza
GROUP BY NumeroEmpleado
HAVING COUNT(1) = (SELECT MAX(COUNT(1)) FROM Limpieza GROUP BY NumeroEmpleado)
) T ON E.Id = T.NumeroEmpleado