Mysql 具有多个联接的查询的写入计数查询

对于SpringJPA，我使用下面的本机查询，需要实现分页。为此，我需要一个count查询，它将返回由below查询返回的行。如何编写计数查询

SELECT  count(distinct opportunity_vendors.opportunity_id) as oppcount, vendors.name , count(applications.id) as appcount
FROM public.vendors 
  inner join public.opportunity_vendors on vendors.id = opportunity_vendors.vendor_id
  inner join public.opportunities on opportunity_vendors.opportunity_id = opportunities.id
  inner join public.applications on opportunity_vendors.opportunity_id = applications.opportunity_id
  group by vendors.name having length(vendors.name) > 0;```

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您可以将该查询用作子查询。。一个简单的方法是

select count(*) 
from (

    SELECT  count(distinct opportunity_vendors.opportunity_id) as oppcount
        , vendors.name 
        , count(applications.id) as appcount
    FROM public.vendors 
      inner join public.opportunity_vendors on vendors.id = opportunity_vendors.vendor_id
      inner join public.opportunities on opportunity_vendors.opportunity_id = opportunities.id
      inner join public.applications on opportunity_vendors.opportunity_id = applications.opportunity_id
      group by vendors.name 
      having length(vendors.name) > 0; 

) t 

---

您可以这样做：

select count(*) from (
SELECT  count(distinct opportunity_vendors.opportunity_id) as oppcount, vendors.name , count(applications.id) as appcount
FROM public.vendors 
  inner join public.opportunity_vendors on vendors.id = opportunity_vendors.vendor_id
  inner join public.opportunities on opportunity_vendors.opportunity_id = opportunities.id
  inner join public.applications on opportunity_vendors.opportunity_id = applications.opportunity_id
  group by vendors.name having length(vendors.name) > 0
) d

致以最良好的祝愿， 比亚尼