結合列與不同的查詢sql

Question

我有3個查詢，但我想把它們合併成一個（有三列）。 this are my results

這是我的代碼：

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') 

你能幫我結合成一個 '選擇'？

Answer 1

條件聚集看起來這正確做法：

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

簡單的答案是：

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 

話雖這麼說，我強烈建議考慮在這裏卸下子查詢。

事情是這樣的：

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

Answer 3

爲什麼你不能嘗試呢？

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