Question

我有各种球队和不同年份的比赛得分列表。

数据库看起来像这样：

id |team|year|week|points
1 | Wildcats|2015|1|43
2 | Wildcats|2015|2|50

我想创建一个显示，显示数据库中的每个团队，该年度得分总分以及该年度的联盟平均分数。

所以它可能看起来像：

Wildcats 2015  387  44.3

等

我正在尝试这个，但它不起作用：

SELECT g1.year, g1.team, xyz.total 
FROM game g1
join (SELECT avg(points) as total, year
            FROM game g2) xyz on g1.year=xyz.year
group by g1.year, g1.team

Answer 1

您可以使用相关子查询来获得每年的平均点数：

SELECT team, year, SUM(points) AS totalPoints,  
       (SELECT AVG(points)
        FROM game AS g2
        WHERE g2.year = g1.year) AS avgPoints
FROM game AS g1
GROUP BY team, year

Demo here

或者，加入派生表：

SELECT g1.team, g1.year, SUM(g1.points) AS totalPoints,  
       g2.avgPoints
FROM game AS g1
JOIN (SELECT AVG(points) AS avgPoints, year
      FROM game
      GROUP BY year
) AS g2 ON g1.year = g2.year
GROUP BY team, year

Demo here

Answer 2

可以查询此查询：

select team,year,sum(points)as total,cast(avg(points)as decimal(10,1))  
  as average from your_table_name group by team,year

将表连接到自身以显示平均值？

2 个答案: