select * from ( select uid ,min(date(in_time)) dt from tb_user_log group by uid) as t1 left join (select uid , date(in_time) dt from tb_user_log union select uid , date(out_time) from tb_user_log) as t2 语法检查

这个SQL语句会检查语法是否正确。以下是经过修正的查询语句：

SELECT *
FROM (
    SELECT uid, MIN(DATE(in_time)) AS dt
    FROM tb_user_log
    GROUP BY uid
) AS t1
LEFT JOIN (
    SELECT uid, DATE(in_time) AS dt
    FROM tb_user_log
    UNION
    SELECT uid, DATE(out_time)
    FROM tb_user_log
) AS t2;

请注意，这个查询会从 `tb_user_log` 表中选择每个用户的最早登录日期，并将其与所有登录和登出日期进行联接。