mysql resturn value as min or plus from sum

Question

對於我的投票系統，我有兩種可能的投票值。 1或-1，這個確切的值被保存在數據庫中。

現在我選擇/計數像field_up和field_down分開的值。我想改變我的查詢輸出只有一個值，如：

如果我們有'+6'和-5它應該返回+1（帶+） 如果我們有-3和+2它應該返回-1（帶 - ）

現在我有後續查詢提前

SELECT 
SUM(CASE thumb when 1 then 1 else 0 end) AS "thumbs_up", 
SUM(CASE thumb when -1 then 1 else 0 end) AS "thumbs_down" 
FROM ..etc 

謝謝！

Thea。

Answer 1

SELECT SUM(thumb) AS votes FROM your_table 

Answer 2

試試這個

SELECT 
SUM(CASE WHEN thumb =1 THEN 1 ELSE 0 END) as "thumbs_up", 
SUM(CASE WHEN thumb =-1 THEN 1 ELSE 0 END) as "thumbs_down", 

FROM ..etc 

Answer 3

夫婦的事情。您可以大大簡化您的查詢到這一點：

SELECT 
SUM(thumb = 1) AS thumbs_up, 
SUM(thumb = -1) AS thumbs_down 
FROM ..etc 

因爲在MySQL（只）true是1和false是0。

其次，你需要查詢了該查詢來調整輸出：

SELECT concat(if(thumbs_up > thumbs_down, '+', ''), thumbs_up - thumbs_down) 
FROM (
SELECT 
    SUM(thumb = 1) AS thumbs_up, 
    SUM(thumb = -1) AS thumbs_down 
    FROM ..etc 
) x