Mysql SQL联合订单（按日期从最晚到最早）

我应该如何按从最晚到最早的预定日期播放此查询？提前感谢

$query = "(SELECT ref_num, event_type, time_scheduled, date_scheduled, date_apply as a, time_apply as t, m_lname as b, m_fname as c, f_fname as d, `read` as r,  'wedding' as type FROM wedding) 
           UNION
           (SELECT ref_num, event_type, time_scheduled, date_scheduled, date_apply as a, time_apply as t, c_lname as b, c_fname as c, c_mname as d, `read` as r, 'baptism' as type FROM baptism) 
           ORDER BY date_scheduled DESC LIMIT 15
           ";

试试这个

$query = "SELECT ref_num, event_type, time_scheduled, date_scheduled, a, t, b, c, d, r, type from (SELECT ref_num, event_type, time_scheduled, date_scheduled, date_apply as a, time_apply as t, m_lname as b, m_fname as c, f_fname as d, `read` as r,  'wedding' as type FROM wedding) 
           UNION
           (SELECT ref_num, event_type, time_scheduled, date_scheduled, date_apply as a, time_apply as t, c_lname as b, c_fname as c, c_mname as d, `read` as r, 'baptism' as type FROM baptism) as tmp
           ORDER BY date_scheduled DESC LIMIT 15
           ";

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你能澄清到底是什么问题吗？我不明白为什么这不起作用？我认为这与他们现有的查询没有任何不同，是吗？