mysql - 根据总计数获取当前状态

Question

我在 mysql 查询上设置条件(if then else)时遇到问题。

简单来说，我有 3 个相互关联的表。

m_shift_schedule    site_shift_schedule      m_ticket
================    ===================     ============
* shift_id   ======> * shift_id             * ticket_id
* start_time         * shift_date           * ticket_status
* end_time           * user_id   ========>  * ticket_served_by

我现在的查询:

SELECT user_id
FROM site_shift_schedule
LEFT JOIN m_shift_schedule ON site_shift_schedule.shift_id = m_shift_schedule.shift_id
WHERE site_shift_schedule.shift_date =  '2019-02-11';

如果我想让输出变成这样，我该怎么办？

空闲 = m_ticket.ticket_status(4 或 5 或 6) 和总数 m_ticket.ticket_served_by < 2

忙碌 = m_ticket.ticket_status(4 或 5 或 6) 且总数 m_ticket.ticket_served_by = 2

过载 = m_ticket.ticket_status(4 或 5 或 6) 且总数 m_ticket.ticket_served_by > 2

      user_id                           Status
  =============================       ============
 ismail.rahman.saanin@random.co          Idle
 lutfi.aldi.nugroho@random.co            Busy

大家帮帮我吧，谢谢。 。 .

Answer 1

您可以尝试使用CASE WHEN Expression和Group By

SELECT user_id,
case when count(m_ticket.ticket_served_by)<2 then 'idle' 
     when count(m_ticket.ticket_served_by)=2 then 'Busy' 
     when count(m_ticket.ticket_served_by)>2 then 'Overload' end as status
FROM site_shift_schedule
LEFT JOIN m_shift_schedule ON site_shift_schedule.shift_id = m_shift_schedule.shift_id
left join m_ticket on site_shift_schedule.user_id=m_ticket.ticket_served_by
WHERE site_shift_schedule.shift_date =  '2019-02-11' and m_ticket.ticket_status in (4,5,6)
group by user_id