Question

对于我的投票系统，我有两个可能的投票值。 1或-1，这个确切的值保存在数据库中。

现在我选择/计算分隔的值，如field_up和field_down。我想更改我的查询只输出一个值，如：

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

现在我有以下查询

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

提前致谢！

特亚。

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

一些事情。您可以大大简化您的查询：

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

因为在mysql中（仅）true是1而false是0。

其次，您需要查询该查询以调整输出：

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

mysql返回值为min或加上sum

3 个答案: