在where子句的计数内使用select

Question

我有一个问题，我试图从修订计划中选择所有设备，如果我没有为这些设备制作维修单，则必须在本月完成这些计划。我想做这样的事情：

select revision_planning.id_echip as echip_id
from revision_planning
    inner join service_sheet on echip_id=service_sheet.id_echip
where revision_planning.next_rev_date between '2016-10-01' and '2016-10-31'
  and count (select * from service_sheet 
             where echip_id=service_sheet.id_echip
               and service_sheet.`data`between '2016-10-01 00:00:00'and '2016-10-31 23:59:18') = 0
  and revision_planning.employee_name='first_last_name'

Answer 1

尝试如下所示：

select revision_planning.id_echip as echip_id from revision_planning
  inner join service_sheet on echip_id=service_sheet.id_echip
  where revision_planning.next_rev_date between '2016-10-01' and '2016-10-31' and not exists (select 1 from service_sheet 
    where echip_id=service_sheet.id_echip and service_sheet.`data`between '2016-10-01 00:00:00'and '2016-10-31 23:59:18')
 and revision_planning.employee_name='first_last_name'

Answer 2

您可以使用NOT EXISTS语句，而不是在WHERE子句中检查COUNT =0

select revision_planning.id_echip as echip_id 
from revision_planning
inner join service_sheet on echip_id=service_sheet.id_echip
where revision_planning.next_rev_date between '2016-10-01' and '2016-10-31' 
and NOT EXISTS(select 1 from service_sheet 
where echip_id=service_sheet.id_echip and service_sheet.`data`between '2016-10-01 00:00:00'and '2016-10-31 23:59:18')
and revision_planning.employee_name='first_last_name'