Question

我正在尝试对列进行求和以在体育网站上显示统计信息。我的mysql查询是

SELECT s.schoolid, s.season, s.playerid, SUM(s.serviceaces) AS sumAces, SUM(s.attackkills) AS sumKills, SUM(s.assists) AS sumAssists, p.fname, p.lname 
FROM `stats` AS s 
LEFT JOIN `players` AS p ON p.id = s.playerid 
GROUP BY s.playerid 
HAVING s.schoolid = 2 AND s.season = 2015

这将给我9条记录。它应该给我12，因为第2队有12名球员，并且都输入了统计数据。如果我将查询更改为

的简单选择查询

SELECT s.*, p.fname, p.lname 
FROM `stats` AS s 
LEFT JOIN `players` AS p ON p.id = s.playerid 
WHERE s.schoolid = 2 AND s.season = 2015

我返回24条记录。这是有道理的，因为为这支12人队输入了两场比赛的统计数据。

当我尝试将我的专栏和按玩家分组时，我做错了什么？

编辑这是一个sql小提琴链接 - http://sqlfiddle.com/#!9/e5cf5/1/0）

我发现了问题，失踪人员有2014年的统计数据。我会阅读Ollie的链接，看看这是不是我的问题。

所以看起来我的解决方案就像添加WHERE s.season = 2015 AND s.schoolid = 2一样简单，以便最终查询

SELECT s.schoolid, s.season, s.playerid, SUM(s.serviceaces) AS sumAces, SUM(s.attackkills) AS sumKills, SUM(s.assists) AS sumAssists, p.fname, p.lname 
FROM `stats` AS s 
LEFT JOIN `players` AS p ON p.id = s.playerid
WHERE s.season = 2015
GROUP BY s.playerid

我在编辑时错过了Hitesh的回答。他做对了。

Answer 1

对于这类问题，请发布表格模式和样本记录转储以及所需的结果，以便我们进行测试。我认为这可以帮到你。

SELECT s.schoolid, s.season, s.playerid, SUM(s.serviceaces) AS sumAces, SUM(s.attackkills) AS sumKills, SUM(s.assists) AS sumAssists, p.fname, p.lname 
    FROM `stats` AS s 
    LEFT JOIN `players` AS p ON p.id = s.playerid 
    WHERE s.schoolid = 2 AND s.season = 2015
    GROUP BY s.playerid

Answer 2

切换您的from和left join条款 - 您希望从players'侧驱动查询并显示缺少统计信息的null，而不是其他方式：

SELECT    s.schoolid,
          s.season,
          s.playerid,
          SUM(s.serviceaces) AS sumAces,
          SUM(s.attackkills) AS sumKills,
          SUM(s.assists) AS sumAssists,
          p.fname,
          p.lname 
FROM      `players` AS p 
LEFT JOIN `stats` AS s ON p.id = s.playerid 
GROUP BY  s.playerid 
HAVING    s.schoolid = 2 AND s.season = 2015

按查询分组不返回所有值

2 个答案: