这段sql出错在哪儿，如何解决？

Question

(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，语法没问题呀 ？？？？？

Answer 1

原因：没有选择数据库
解决方案：
1.命令行下使用：select dbname;
2.代码中要配置好项目使用的数据库；