連接表並返回正確的聚合

Question

我正在使用Sean Lahman的“棒球”數據庫來匯總2010年至2015年之間各隊的奔跑，命中和“擊球”，獲勝情況。我想加入“隊”和“擊球”表，並使用teamID上的分組功能返回總金額在“團隊”表中按團隊查看奔跑，命中，擊球以及獲勝和失利。

例如，從“團隊”表中，我想逐年返回勝負

team ID Name             Wins  Losses Year
ARI Arizona Diamondbacks    65  97  2010
ARI Arizona Diamondbacks    94  68  2011

從打擊表中，這是我想要的輸出

year   teamID Runs Hits  At Bats
2012    ARI 734   1416  5462
2015    ARI 720  1494   5649

我嘗試了以下查詢，但它返回了獲勝和虧損列的膨脹值：

select b.yearID, b.teamID, SUM(b.R) as Runs, SUM(b.H) as Hits, SUM(b.AB) as At_Bats, 
t.name as Team_Name, SUM(t.W) as Wins, SUM(t.L) as Losses
from Batting b, Teams t
where b.teamID = t.teamID and b.yearID=t.yearID and b.yearID between '2010' and '2015'
group by b.teamID, b.yearID, t.name, t.W, t.L
order by b.teamID 

可以在此處找到數據庫的文檔http://www.seanlahman.com/files/database/readme2017.txt

Answer 1

盡管我在文檔中找不到該記錄，但是我猜想teamID和yearID的每個組合都唯一標識Teams表中的記錄。 在總結贏與輸時，您可以將它們乘以相關玩家的數量。 所以不要在tW和tL上求和：

select b.yearID, b.teamID, SUM(b.R) as Runs, SUM(b.H) as Hits, SUM(b.AB) as At_Bats, 
t.name as Team_Name, t.W as Wins, t.L as Losses
from Batting b, Teams t
where b.teamID = t.teamID and b.yearID=t.yearID and b.yearID between '2010' and '2015'
group by b.teamID, b.yearID, t.name, t.W, t.L
order by b.teamID