在许多其他DBMS（Oracle，sql-Server，Postgres）中，可以使用窗口函数：
SELECT id, file, folder, added
FROM
( SELECT id, file, folder, added,
DENSE_RANK() OVER (ORDER BY added DESC) AS d_rank,
ROW_NUMBER() OVER (PARTITION BY added ORDER BY id DESC) AS row_no
FROM AviationImages
) d
WHERE d_rank <= 5 -- limit number of dates
AND row_no <= 5 ; -- limit number of images per date
SELECT i.id, i.file, i.folder, i.added
FROM
( SELECT DISTINCT added
FROM AviationImages
ORDER BY added DESC
LIMIT 5
) AS da
JOIN
AviationImages AS i
ON i.added = da.added
AND i.id >= COALESCE(
( SELECT ti.id
FROM AviationImages AS ti
WHERE ti.added = da.added
ORDER BY ti.id DESC
LIMIT 1 OFFSET 4
), -2147483647) ; -- use 0 if the `id` is unsigned int
索引打开(added, id)将有助于提高效率-如果表使用InnoDB并且id为主键，则仅索引打开(added)就足够了。
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