顯示行與零值

Question

我有以下查詢顯示基於性別的人數：

SELECT gender, 
    count(*) AS count 
FROM persons 
    CROSS JOIN (SELECT count(*) AS total 
       FROM persons) x 
GROUP BY 1 
ORDER BY gender DESC 

隨着作爲結果：

Male | 5 

與零值如何也同樣顯示的行如：

Male | 5 
Female | 0 

Answer 1

一個簡單的辦法，找出男性的計數/女

SELECT 
    SUM(gender='Male') AS `Male`, 
    SUM(gender='Female') AS `Female` 
FROM persons 
GROUP BY gender 

這將產生像

Male Female 
5  0 

或顯示一行輸出聰明人，你可以使用union

SELECT 'Male' AS gender,COUNT(*) `count` FROM persons WHERE gender='Male' 
UNION 
SELECT 'Female' AS gender,COUNT(*) `count` FROM persons WHERE gender='Female' 

這將輸出作爲

gender count 

Male 5 
Female 0 

Answer 2

好吧，如果你「尋找的東西其實跟性別一樣快，你總是可以用UNION ALL吧。

SELECT [Gender], COUNT(*) [Total] FROM [Persons] WHERE [Gender] = 'Male' GROUP BY [Gender] 

UNION ALL 

SELECT [Gender], COUNT(*) [Total] FROM [Persons] WHERE [Gender] = 'Female' GROUP BY [Gender]