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

I WANT THE OUTPUT LIKE THIS

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

I have tried this below query

$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";

I want to show active and idle status of the driver based on last_viewed column. For example agent_id 2 have three drivers (1,2,3) and those 3 drivers have 1,0,0 in their last_viewed column. So, i want to show the output like this 1 active and 2 idle...

Answer 1

try this,.

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

here is SQLFiddle