这是我的疑问：
select a.id, a.title,count(x.id) as Orders
-- from x_vendordeliveriesareas vda
-- left join x_vendordeliveries vd
-- on vd.id = vda.vendordelivery_id
from x_orders x
left join x_areas a
on x.delivery_area_id = a.id
-- on vda.area_id = a.id
-- left join x_orders x
left join x_vendors v
on v.id = x.vendor_id
where v.title like 'golden dragon%' and (date_format(x.date,'%Y-%m-%d') BETWEEN '2015-01-01' AND '2015-06-30')
and x.status_id=11
and x.country_id =11
and v.city_id=3
group by 1;
这很好用，但我想返回那些有0个订单的区域。 我尝试过IFNULL并合并函数
答案 0 :(得分：2)
您的驾驶表应为$(document).ready(function() {
：
x_areas请注意，我移动了select
a.id,
a.title,
coalesce(count(x.id), 0) as Orders
from x_areas a
left join x_orders x
on x.delivery_area_id = a.id
and x.status_id = 11
and x.country_id = 11
and (date_format(x.date,'%Y-%m-%d') BETWEEN '2015-01-01' AND '2015-06-30')
left join x_vendors v
on v.id = x.vendor_id
where
v.title like 'golden dragon%'
and v.city_id = 3
group by 1;
条款中的部分WHERE条件，以防止ON变成LEFT JOIN，从而产生相同的结果已添加INNER JOIN 0订单。