mysql从sum中以最小值或加号重新返回值

对于我的投票制度，我有两种可能的价值观可以投票支持。1或-1，此值正好保存在数据库中

现在我选择/计算像field\u up和field\u down这样分开的值。我想将查询更改为只输出一个值，如下所示：

如果我们有“+6”和-5，它应该返回+1（带+） 如果我们有-3和+2i，它应该返回-1（带-）

现在我有以下问题

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

提前谢谢

Thea.

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

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

---

两件事。您可以将查询简化为：

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

---

两件事。您可以将查询简化为：

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

---

@你可以尝尝新鲜茶this@Freshtea你可以试试这个