CODE EXAMPLE FOR SQL

Raw query must include the primary key

Include 1 as id to your query

Message.objects.raw('''
        SELECT 1 as id , s1.ID, s1.CHARACTER_ID, MAX(s1.MESSAGE) MESSAGE, MAX(s1.c) occurrences
        FROM
           (SELECT ID, CHARACTER_ID, MESSAGE, COUNT(*) c
            FROM tbl_message WHERE ts > DATE_SUB(NOW(), INTERVAL %s DAY) GROUP BY CHARACTER_ID,MESSAGE) s1
        LEFT JOIN
           (SELECT ID, CHARACTER_ID, MESSAGE, COUNT(*) c
            FROM tbl_message WHERE ts > DATE_SUB(NOW(), INTERVAL %s DAY) GROUP BY CHARACTER_ID,MESSAGE) s2
          ON s1.CHARACTER_ID=s2.CHARACTER_ID
         AND s1.c < s2.c
        WHERE s2.c IS NULL
        GROUP BY CHARACTER_ID
        ORDER BY occurrences DESC''', [days, days])