如何从多个查询中进行乘法和除法？

Question

所以现在我有3个疑问：

让我们把这个查询x

SELECT count(*) as totalDrink from 
Drink D join History H where H.drinkName = D.name AND type = 'vodka' and userID = 'sai' 

查询Ÿ

SELECT count(*) as totalDrink from 
Drink D join Favorite F where F.drinkName = D.name AND type = 'vodka' and userID = 'sai' 

查询ž

SELECT SUM(totalDrinks) as total FROM (
SELECT COUNT(*) totalDrinks FROM History 
WHERE userID = 'sai' 
UNION ALL 
SELECT COUNT(*) FROM Favorite 
WHERE userID = 'sai' 
) as totalDrink 

基本上我想要做的mySQL和输出：

（X + Y（0.666））/ Z

Answer 1

大多数直接：

SELECT (
    (
    SELECT COUNT(*) 
    FROM Drink D JOIN History H ON H.drinkName = D.name 
    WHERE type = 'vodka' AND userID = 'sai' 
) + (
    SELECT COUNT(*) 
    FROM Drink D JOIN Favorite F ON F.drinkName = D.name 
    WHERE type = 'vodka' AND userID = 'sai' 
) 
)/(
    (
    SELECT COUNT(*) FROM History WHERE userID = 'sai' 
) + (
    SELECT COUNT(*) FROM Favorite WHERE userID = 'sai' 
) 
)