This SQL query will select least recently played track from category ID 44 and fall back to category ID 25 if first query doesn't return a result.

SELECT * FROM (
        SELECT `songs`.`ID`, `songs`.`artist`, `songs`.`title`, `songs`.`date_played`, `songs`.`id_subcat`, 1 AS `preference` FROM `songs`
        LEFT JOIN `queuelist` ON ( `songs`.`artist` = `queuelist`.`artist`)
        WHERE `songs`.`enabled` = 1
        AND `songs`.`song_type` = 0
        AND `songs`.`id_subcat` = 44
        AND (`songs`.`start_date` <= NOW() OR `songs`.`start_date` = '2002-01-01 00:00:01')
        AND (`songs`.`end_date` >= NOW() OR `songs`.`end_date` = '2002-01-01 00:00:01')
        AND (TIMESTAMPDIFF(MINUTE, `songs`.`date_played`, NOW()) > $TrackRepeatInterval$)
        AND (TIMESTAMPDIFF(MINUTE, `songs`.`artist_played`, NOW()) > $ArtistRepeatInterval$)
        AND  `queuelist`.`artist` IS NULL
        LIMIT 1

    UNION

        SELECT `songs`.`ID`, `songs`.`artist`, `songs`.`title`, `songs`.`date_played`, `songs`.`id_subcat`, 2 AS `preference` FROM `songs`
        LEFT JOIN `queuelist` ON ( `songs`.`artist` = `queuelist`.`artist`)
        WHERE `songs`.`enabled` = 1
        AND `songs`.`song_type` = 0
        AND `songs`.`id_subcat` = 25
        AND (`songs`.`start_date` <= NOW() OR `songs`.`start_date` = '2002-01-01 00:00:01')
        AND (`songs`.`end_date` >= NOW() OR `songs`.`end_date` = '2002-01-01 00:00:01')
        AND (TIMESTAMPDIFF(MINUTE, `songs`.`date_played`, NOW()) > $TrackRepeatInterval$)
        AND (TIMESTAMPDIFF(MINUTE, `songs`.`artist_played`, NOW()) > $ArtistRepeatInterval$)
        AND  `queuelist`.`artist` IS NULL

    ORDER BY `date_played`
    LIMIT 2
)temp
ORDER BY `preference`
LIMIT 1;

This query selects least recently played track from category ID 44 and excludes genres of last two tracks in playlist:

SELECT `songs`.`ID`, `songs`.`artist`, `songs`.`title`, `songs`.`id_genre` FROM `songs`
LEFT JOIN `queuelist` ON ( `songs`.`artist` = `queuelist`.`artist`)

LEFT JOIN (
    SELECT `songs`.`id_genre` FROM `queuelist`
    LEFT JOIN `songs` ON (`songs`.`ID` = `queuelist`.`songID`)
    ORDER BY queuelist.ID DESC
    LIMIT 2
) AS queue_genre ON (songs.id_genre = queue_genre.id_genre)

WHERE `songs`.`enabled` = 1
AND `songs`.`song_type` = 0

AND `songs`.`id_subcat` = 44

AND (`songs`.`start_date` <= NOW() OR `songs`.`start_date` = '2002-01-01 00:00:01')
AND (`songs`.`end_date` >= NOW() OR `songs`.`end_date` = '2002-01-01 00:00:01')
AND (TIMESTAMPDIFF(MINUTE, `date_played`, NOW()) > $TrackRepeatInterval$)
AND (TIMESTAMPDIFF(MINUTE, `artist_played`, NOW()) > $ArtistRepeatInterval$)
AND  `queuelist`.`artist` IS NULL

AND queue_genre.id_genre IS NULL

ORDER BY `date_played` ASC
LIMIT 1

Note: You can get top whatever played only if history table contains data for the time period you need.

-- Select Top10 tracks from July 2016
SELECT songs.ID, songs.artist, songs.title, COUNT(*) AS spins, SUM(history.listeners) as total_listeners
FROM `songs`
LEFT JOIN `history` ON (songs.title = history.title AND songs.artist = history.artist)

-- This is the date range filter
WHERE history.date_played BETWEEN '2016-07-01' AND '2016-08-01'

AND songs.song_type = 0

GROUP BY history.title, history.artist
ORDER BY spins DESC
LIMIT 10;