连接多个表并根据第一个表id获取状态

Question

AGENT DB TABLE

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

DRIVER DB TABLE

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

我想要输出这个

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

我在下面尝试了这个查询

$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";

我想基于last_viewed列显示驱动程序的活动和空闲状态。例如，agent_id 2有三个驱动程序（1,2,3），这3个驱动程序在last_viewed列中有1,0,0个。所以，我想显示输出，如1活跃和2空闲......

Answer 1

这是你在看什么？

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

<强> DEMO

UODATE ： 来自上次评论

  

我不想要司机详细信息 - ＆gt; 1个驱动程序（活动0 | 1空闲）我想要   驱动程序数量 - ＆gt; 1驱动程序，有效 - ＆gt; 0，空闲 - ＆gt; 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

Answer 2

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

这里是SQLFiddle