如何通過/子查詢創建多個MySQL計數/分組？

Question

我在我的數據庫中有一張包含足球結果的表格，相關列爲matchNumber（基於日期的數字），Result（「W」，「D」或「L」）goalsFor，goalsAg和manager。

我有這個疑問：

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; 

返回以下結果：

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

這完美的作品。但是，結果會跨越多個季節，我希望打破查詢的輸出以反映這一點。我曾嘗試以下：

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; 

此查詢的結果可以在此圖像中可以看出：

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

正如你所看到的， '季節'， 'P'，「F '和'A'列給了我想要的結果，但剩下的列正在重複總計。因此，我的問題是，如何調整我的查詢，使'W'，'D'和'L'列在輸出的每一行中給出逐年總計，而不是總數？

Answer 1

問題是你的三個子查詢不會限制他們按季節計數。嘗試將其更改爲：

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;