Question

我有3个查询，但我想将它们合并为一个（有三列）。 this are my results

这是我的代码：

Select family = count(s.destiny) from rental
inner join cars as s on s.number_car = ID_car 
where s.destiny in (select destiny from cars where destiny like 'kids') 

Select lux = count(s.destiny) from rental
inner join cars as s on s.number_car = ID_car
where s.destiny in (select destiny from cars where destiny like 'luxury')

Select sports = count(s.destiny) from rental
inner join cars as s on s.number_car = ID_car
where s.destiny in (select destiny from cars where destiny like 'sport car')

你能帮我把它组合成'select'吗？

Answer 1

条件聚合似乎是这种正确的方法：

Select sum(case when density = 'kids' then 1 else 0 end) as family,
       sum(case when density = 'lux' then 1 else 0 end) as luxury,
       sum(case when density = 'sport car' then 1 else 0 end) as sports       
from rental r inner join
     cars s
     on s.number_car = ID_car ;

Answer 2

简单的答案是：

SELECT 
(
Select family = count(s.destiny) from rental
inner join cars as s on s.number_car = ID_car 
where s.destiny in (select destiny from cars where destiny like 'kids') 
) as kids,
(
Select lux = count(s.destiny) from rental
inner join cars as s on s.number_car = ID_car
where s.destiny in (select destiny from cars where destiny like 'luxury')
) as luxury,
(
Select sports = count(s.destiny) from rental
inner join cars as s on s.number_car = ID_car
where s.destiny in (select destiny from cars where destiny like 'sport car')
) as sportsCar

话虽如此，我强烈建议您考虑在此处删除子查询。

这样的事情：

SELECT destiny, COUNT(1)
FROM cars
GROUP BY destiny

Answer 3

为什么你不能尝试这个？

Select destiny,count(*) from rental
inner join cars as s on s.number_car = ID_car
where s.destiny in ( 'cars','luxury')
group by destiny

将列与不同的查询组合在一起

3 个答案: