Question

MYSQL中的某位用户如何将日期条目中的用户百分比与其他日期条目和得分进行比较，从而有效地将用户百分比从一个日期返回到另一个日期？

我一直试图绕过这个问题几天，但我的想法已经用完了，觉得我的sql知识有限。不确定我是否应该使用连接或子查询？ MYSQL表包含3个字段，名称，分数和日期。

表：userData

name    score   date

joe      5      2014-01-01
bob     10      2014-01-01
joe     15      2014-01-08
bob     12      2014-01-08

返回了查询提示

user    %inc    last date

joe     33%     2014-01-08
bob     17%     2014-01-08

似乎这样一个简单的函数，一个数据库可以服务但试图理解这是我的掌握？

Answer 1

您需要使用SUBQUERIES。类似的东西：

  SELECT name,
         ((SELECT score
             FROM userData as u2
            WHERE u2.name = u1.name
         ORDER BY date desc
            LIMIT 1
          ) 
          /
          (
            SELECT score 
              FROM userData as u3
             WHERE u3.name = u1.name
          ORDER BY date desc
             LIMIT 1,1
          ) 
          * 100.0
         ) as inc_perc,
         max(date) as last_date
    FROM userData as u1
GROUP BY name

Answer 2

简单解决方案假设％Inc列的公式=总计/总和* 100

select name,total/sum * 100, date from (
select name,sum(score) as total,count(*) as num,date from table group by name
)as resultTable

Answer 3

select a.name as [user],(cast(cast(b.score as float)-a.score as float)/cast(a.score as float))*100 as '% Inc',b.[date] as lastdate 
from userdata a inner join userdata b on a.name = b.name and a.date < b.date

我猜您正在寻找与过去日期相比得分增加百分比

Answer 4

另一种方式（注意，我有另一个结果。基于名称＆＃34; percinc＆＃34;，百分比增加，我在我眼中正确计算。如果你想要你的结果，只需用{计算它} {1}}）：

示例数据：

t1.score / t2.score * 100

查询：

CREATE TABLE t
    (`name` varchar(3), `score` int, `date` varchar(10))
;

INSERT INTO t
    (`name`, `score`, `date`)
VALUES
    ('joe', 5, '2014-01-01'),
    ('bob', 10, '2014-01-01'),
    ('joe', 15, '2014-01-08'),
    ('bob', 12, '2014-01-08')
;

结果：

select
t1.name,
t1.score first_score,
t1.date first_date,
t2.score last_score,
t2.date last_date,
t2.score / t1.score * 100 percinc
from
t t1
join t t2 on t1.name = t2.name
where
t1.date = (select min(date) from t where t.name = t1.name)
and t2.date = (select max(date) from t where t.name = t1.name);

live demo

相同的列计算/百分比

4 个答案: