mysql resturn value as min or plus from sum

Question

对于我的投票系统，我有两种可能的投票值。 1或-1，这个确切的值被保存在数据库中。

现在我选择/计数像field_up和field_down分开的值。我想改变我的查询输出只有一个值，如：

如果我们有'+6'和-5它应该返回+1（带+） 如果我们有-3和+2它应该返回-1（带 - ）

现在我有后续查询提前

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 

谢谢！

Thea。

Answer 1

SELECT SUM(thumb) AS votes FROM your_table 

Answer 2

试试这个

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

夫妇的事情。您可以大大简化您的查询到这一点：

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

因为在MySQL（只）true是1和false是0。

其次，你需要查询了该查询来调整输出：

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