如何创建多个MySQL计数/分组/子查询？

Question

我的数据库中有一个表，其中包含足球结果，相关的列是matchNumber（基于日期的数字），Result（“ W”，“ D”或“ L”），goalFor，goalAg和Manager。

我有这个查询：

SELECT COUNT(*) AS P,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "W") AS W,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "D") AS D,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "L") AS L,  
SUM(GoalsFor) AS F,  
SUM(GoalsAg) AS A,  
ROUND((SELECT SUM((((SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "W") * 2) +(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "D")))/((SELECT COUNT(*) FROM match_results WHERE manager = 13)*2)*100),2) AS pct  
FROM match_results WHERE manager = 13;

返回以下结果：

P   W  D  L  F   A   Pct  
213 92 49 72 296 247 54.69

这很完美。 但是，结果跨越多个季节，我想分解查询的输出以反映这一点。 我尝试了以下方法：

SELECT LEFT(matchNumber,4) AS Season,  
COUNT(*) AS P,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "W") AS W,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "D") AS D,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "L") AS L,  
SUM(GoalsFor) AS F,  
SUM(GoalsAg) AS A,  
ROUND((SELECT SUM((((SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "W") * 2) +(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "D")))/((SELECT COUNT(*) FROM match_results WHERE manager = 13)*2)*100),2) AS pct  
FROM match_results WHERE manager = 13  
GROUP BY Season;

该查询的结果可以在以下图像中看到：

http://www.kidderminsterharriers.com/images/query2.jpg

如您所见，“季节”，“ P”，“ F”和“ A”列给了我想要的结果，但其余列重复了总数。 因此，我的问题是如何调整我的查询，以使“ W”，“ D”和“ L”列在输出的每一行中也逐年提供总计而不是总计？

Answer 1

问题是您的三个子查询没有按季节限制它们的数量。 尝试将其更改为：

SELECT @season:=LEFT(matchNumber,4) AS Season,  
COUNT(*) AS P,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "W" AND LEFT(matchNumber,4)=@season) AS W,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "D" AND LEFT(matchNumber,4)=@season) AS D,  
(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "L" AND LEFT(matchNumber,4)=@season) AS L,  
SUM(GoalsFor) AS F,  
SUM(GoalsAg) AS A,  
ROUND((SELECT SUM((((SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "W") * 2) +(SELECT COUNT(*) FROM match_results WHERE manager = 13 AND Result = "D")))/((SELECT COUNT(*) FROM match_results WHERE manager = 13)*2)*100),2) AS pct  
FROM match_results WHERE manager = 13  
GROUP BY Season;