這段sql出錯(cuò)在哪兒，如何解決？

(SELECT *
FROM `dozhan_reply` t1
WHERE `reply_parent` IN (
    SELECT `reply_id`
    FROM (
        SELECT `reply_id`
        FROM `dozhan_reply`
        WHERE `reply_article` = 69
            AND `reply_type` = 0
        LIMIT 0, 5
    ) t
))
UNION
(SELECT *
FROM `dozhan_reply`
WHERE `reply_article` = 69
    AND `reply_type` = 0
LIMIT 0, 5)
UNION
SELECT DISTINCT b1.reply_user, b2.avatar_link
FROM `dozhan_reply` b1, `dozhan_user` b2
WHERE `reply_article` = 69
    AND b1.reply_user = b2.username

求解，搞不懂，語法沒問題呀 ？？？？？