连接多个表并根据第一个表id获取状态

Question

代理数据库表

agent_id  agent_name company_name
--------  ----------  -----------
1         AAA           XXX
2         BBB           YYY
3         CCC           ZZZ
4         DDD           XYZ

驱动数据库表

agent_id  driver_id   driver_name last_viewed
--------  ----------  ----------- -----------
2         1           EEE           1
2         2           FFF           0
2         3           GGG           0
1         4           HHH           0
3         5           III           1
3         6           JJJ           1

我想要这样的输出

Agent Details     Driver details

1, AAA,             1 Drivers (0 active | 1 idle)
Company name

2, BBB,             3 Drivers (1 active | 2 idle)
Company name

3, CCC,             2 Drivers (2 active | 0 idle)
Company name

我已经尝试过以下查询

$sql="SELECT a.*,d.*, COUNT(d.driver_id) AS drivers_count FROM ta_agent a JOIN ta_drivers d USING(agent_id) GROUP BY a.agent_id";

我希望基于last_viewed列显示驱动程序的活动状态和空闲状态。例如，agent_id 2有三个驱动程序(1,2,3)，这3个驱动程序的last_viewed列中有1,0,0。所以，我想把输出显示为1活动和2空闲.

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Answer 1

试试这个。

select a.agent_id, a.agent_name, a.company_name, ifnull(cnt_all,0) total_drivers,ifnull(cnt_active,0) active_drivers, ifnull(cnt_idle,0) idle_drivers
from agent a left join (select agent_id, count(*) cnt_all
                   from driver
                   group by agent_id) cnt on a.agent_id=cnt.agent_id

left join (select agent_id, count(*) cnt_idle
                   from driver
                   where last_viewed=0
                   group by agent_id) idle on a.agent_id=idle.agent_id

left join (select agent_id, count(*) cnt_active
                   from driver
                   where last_viewed=1
                   group by agent_id) active on a.agent_id=active.agent_id

这是SQLFiddle

Answer 2

这就是你要看的吗？

select 
concat(
  a.agent_id,' ',a.agent_name,' ',a.company_name
) as `Agent Details`,
concat(
 COUNT(d.driver_id),' Drivers (',
 ' Active ',sum(d.last_viewed = 1) 
 ,' | ',sum(d.last_viewed = 0 ),' idle ) '
)as `Driver details`

FROM AGENT a
LEFT JOIN DRIVER d USING(agent_id)
GROUP BY a.agent_id

演示

UODATE：来自最后评论

我不想要驱动程序详细信息-> 1驱动程序(活动0\1空闲)，我需要驱动程序-> 1驱动程序的数量，Active -> 0，idle -> 1

select 
concat(
  a.agent_id,' ',a.agent_name,' ',a.company_name
) as `Agent Details`,

concat ( COUNT(d.driver_id),' ',' Drivers')  as `Number of Drivers`,
sum(d.last_viewed = 1) as `Active`,        
sum(d.last_viewed = 0) as `Idle`
FROM AGENT a
LEFT JOIN DRIVER d USING(agent_id)
GROUP BY a.agent_id

http://www.sqlfiddle.com/#!2/53e77/6