Операторы LEFT OUTER JOIN и RIGHT OUTER JOIN, задача 2

--Посчитайте для каждого года число уникальных названий купленных треков.

SELECT EXTRACT(YEAR FROM CAST(i.invoice_date AS DATE)) AS year_of_invoice,
       COUNT(DISTINCT t.name) AS unique_track_count
FROM track AS t
LEFT JOIN invoice_line AS il ON t.track_id = il.track_id
LEFT JOIN invoice AS i ON il.invoice_id = i.invoice_id
GROUP BY year_of_invoice;
привет. в полученном результате выдает ошибку - слишком много строк.
в седьмой строке LEFT на RIGHT поменять надо
либо немного изменить

SELECT EXTRACT(YEAR FROM CAST(i.invoice_date AS DATE)) AS year_of_invoice,
       COUNT(DISTINCT t.name) AS unique_track_count
FROM invoice AS i
LEFT JOIN invoice_line AS il ON i.invoice_id = il.invoice_id
LEFT JOIN track AS t ON il.track_id = t.track_id
GROUP BY year_of_invoice;