相关子查询？从不同的列，同一个表中提取数据

问题描述 投票：0回答：3

我试图使用多个标准从不同的列中提取数据，但是无法弄清楚如何，我相信这是一个我需要的相关子查询，并且已经尝试了几种不同的方法，但无法弄明白。

我希望获得以下类别的迈阿密热火队胜利的平均值+纽约尼克斯队在以下类别中的平均赔率，并将他们合并为一个平均值。

所以这是我对热火的查询，它确切地检索了我想要的东西

SELECT
    box_score.team_name, 
    ROUND(AVG(eFG),3) eFG,
    ROUND(AVG(OPP_eFG),3) OPP_eFG,
    ROUND(AVG(TOV_PCT),3) TOV_PCT,
    ROUND(AVG(OPP_TOV_PCT),3) OPP_TOV_PCT,
    ROUND(AVG(ORB_PCT),3) ORB_PCT,
    ROUND(AVG(DRB_PCT),3) DRB_PCT,
    ROUND(AVG(FTA_RATE),3) FTA_RATE,
    ROUND(AVG(OPP_FTA_RATE),3) OPP_FTA_RATE
FROM box_score
WHERE team_name = 'Miami Heat' AND WIN_LOSS = 'W' AND game_date < '2019-03-07'

我也为尼克斯做了损失，这也导致了我想要的

WHERE team_name = 'New York Knicks' AND WIN_LOSS = 'L' AND game_date < '2019-03-07'

我的问题是尝试将这两者结合成一个查询，我得到热火队胜利的平均值和knick的损失平均值。所有这些信息都来自同一个表格，我可以通过身份证号码或姓名获取团队信息......如果改变了任何内容，我会使用SQLite

这是运行查询的结果，这就是我正在寻找具有平均值的一行数据...但是我希望这些数字在热火和尼克斯损失中的平均值合并为一行

热火的平均值

eFG    OPP_eFG  TOV_PCT  OPP_TOV_PCT  ORB_PCT  DRB_PCT  FTA_RATE  OPP_FTA_RATE
0.603  0.505    0.14     0.126        0.28     0.77     0.235     0.141

这些是尼克斯输球的平均值

eFG    OPP_eFG  TOV_PCT  OPP_TOV_PCT  ORB_PCT  DRB_PCT  FTA_RATE  OPP_FTA_RATE
0.568  0.602    0.146    0.136        0.225    0.787    0.222     0.235

我希望将每个类别的两个组合成1个平均值

但有没有办法让它成为平均值从单独的列中提取数据？

在这种情况下，我对迈阿密热火很感兴趣，所以我有上面的平均值，但我想要做的是将热火队的平均值换成尼克斯队的相应对手（eFG应该与其他人的opp_eFG相关联）团队等等）...所以基本上我正在寻找以下的平均值：

加热eFG和OPP_eFG尼克斯

加热OPP_eFG和eFG尼克斯

加热TOV_PCT和OPP_TOV_PCT尼克斯

加热OPP_TOV_PCT和TOV_PCT尼克斯

加热FTA_RATE和OPP_FTA_RATE尼克斯

加热OPP_FTA_RATE和FTA_RATE尼克斯

仍然希望得到1排作为结果

sql sqlite inner-join correlated-subquery
3个回答
0
投票

一种解决方案是使用条件聚合在单个表扫描（没有连接或子查询）中执行整个操作：

SELECT  
    box_score.team_name, 
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN eFG          END),3) Heat_eFG,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN eFG          END),3) Knicks_eFG,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN OPP_eFG      END),3) Heat_OPP_eFG,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN OPP_eFG      END),3) Knicks_OPP_eFG,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN TOV_PCT      END),3) Heat_TOV_PCT,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN TOV_PCT      END),3) Knicks_TOV_PCT,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN OPP_TOV_PCT  END),3) Heat_OPP_TOV_PCT,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN OPP_TOV_PCT  END),3) Knicks_OPP_TOV_PCT,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN ORB_PCT      END),3) Heat_ORB_PCT,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN ORB_PCT      END),3) Knicks_ORB_PCT,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN DRB_PCT      END),3) Heat_DRB_PCT,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN DRB_PCT      END),3) Knicks_DRB_PCT,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN FTA_RATE     END),3) Heat_FTA_RATE,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN FTA_RATE     END),3) Knicks_FTA_RATE,
    ROUND(AVG(CASE WHEN team_name = 'Miami Heat'      AND WIN_LOSS = 'W' THEN OPP_FTA_RATE END),3) Heat_OPP_FTA_RATE,
    ROUND(AVG(CASE WHEN team_name = 'New York Knicks' AND WIN_LOSS = 'L' THEN OPP_FTA_RATE END),3) Knicks_OPP_FTA_RATE
FROM box_score
WHERE team_name IN ('Miami Heat', 'New York Knicks') AND game_date < '2019-03-07'

如果你想要计算平均值，这是查询的另一个版本，例如，迈阿密的eFG和纽约单一列中的OPP_eFG损失。这仍然依赖于条件聚合。我还通过将条件移到WHERE子句来简化逻辑。

SELECT  
    box_score.team_name, 
    ROUND(AVG(CASE 
        WHEN team_name = 'Miami Heat'      THEN eFG 
        WHEN team_name = 'New York Knicks' THEN OPP_eFG 
    END, 3) Heats_eFG_Knicks_OPP_eFG, 
    ROUND(AVG(CASE 
        WHEN team_name = 'Miami Heat'      THEN OPP_eFG 
        WHEN team_name = 'New York Knicks' THEN eFG 
    END, 3) Heats_OPP_eFG_Knicks_eFG,
    ROUND(AVG(CASE 
        WHEN team_name = 'Miami Heat'      THEN TOV_PCT 
        WHEN team_name = 'New York Knicks' THEN OPP_TOV_PCT 
    END, 3) Heats_TOV_PCT_Knicks_OPP_TOV_PCT,
    ROUND(AVG(CASE 
        WHEN team_name = 'Miami Heat'      THEN OPP_TOV_PCT 
        WHEN team_name = 'New York Knicks' THEN TOV_PCT 
    END, 3) Heats_OPP_TOV_PCT_Knicks_TOV_PCT,
    ROUND(AVG(CASE 
        WHEN team_name = 'Miami Heat'      THEN FTA_RATE 
        WHEN team_name = 'New York Knicks' THEN OPP_FTA_RATE 
    END, 3) Heats_FTA_RATE_Knicks_OPP_FTA_RATE,
    ROUND(AVG(CASE 
        WHEN team_name = 'Miami Heat'      THEN OPP_FTA_RATE 
        WHEN team_name = 'New York Knicks' THEN FTA_RATE 
    END, 3) Heats_OPP_FTA_RATE_Knicks_FTA_RATE
FROM box_score
WHERE 
    game_date < '2019-03-07' 
    AND (
           ( team_name = 'Miami Heat'      AND win_loss = 'W' )
        OR ( team_name = 'New York Knicks' AND win_loss = 'L') 
    )

注意：正如wildpasser评论的那样，你可能想要使用单引号而不是双引号（这是SQL标准）。我全局所有双引号在原始查询中单引号。

1
投票

This answer assumes that you want an AVG(heat)-AVG(knicks), as per original post, not AVG(heatsX OR knicksY)

我想为此推广Common Table Expressions：

WITH selector_heat as (
SELECT
    box_score.team_name, 
    ROUND(AVG(eFG),3) eFG,
    ROUND(AVG(OPP_eFG),3) OPP_eFG,
    ROUND(AVG(TOV_PCT),3) TOV_PCT,
    ROUND(AVG(OPP_TOV_PCT),3) OPP_TOV_PCT,
    ROUND(AVG(ORB_PCT),3) ORB_PCT,
    ROUND(AVG(DRB_PCT),3) DRB_PCT,
    ROUND(AVG(FTA_RATE),3) FTA_RATE,
    ROUND(AVG(OPP_FTA_RATE),3) OPP_FTA_RATE
FROM box_score
WHERE team_name = 'Miami Heat' AND WIN_LOSS = 'W' AND game_date < '2019-03-07' 
)
, selector_knicks as (
...
)
select H.eFG - K.OPP_eFG as magic_nbr
from selector_heat H 
join selector_knicks K ON (1=1)

关于语法的更多细节：https://www.sqlite.org/lang_with.html但现在忽略“递归”位，在这个实例中你不需要它们。

或者（并且稍微不同的接近角度）您可以使用Window子句聚合“每个团队”然后使用结果。更多信息：https://www.sqlite.org/windowfunctions.html#introduction_to_window_functions

例：

SELECT  
  team_name, 
  WIN_LOSS,
  ROUND(AVG(eFG) OVER (partition by team_name, win_loss),3) as eFG
  ...
  from box_score
  where game_date < '2019-03-07'

使用此结果集，您可以获得所有团队和win_loss组合的平均值。将其包裹在CTE中并在适合的条件下加入其中，例如

WITH cte as (SELECT ...)
SELECT H.eFG - K.OPP_eFG as magic_nbr
FROM cte H join cte K 
  ON (H.team_name = 'Miami Heat' 
  AND K.team_name = 'NY Knicks'
  AND H.win_loss = 'W'
  AND K.win_loss = 'L')
1
投票

如果要先计算平均值然后再计算平均值，可以使用两个级别的聚合：

SELECT ROUND(AVG(eFG), 3) as eFG,
       ROUND(AVG(OPP_eFG), 3) as OPP_eFG,
       ROUND(AVG(TOV_PCT), 3) as TOV_PCT,
       ROUND(AVG(OPP_TOV_PCT), 3) as OPP_TOV_PCT,
       ROUND(AVG(ORB_PCT), 3) as ORB_PCT,
       ROUND(AVG(DRB_PCT), 3) as DRB_PCT,
       ROUND(AVG(FTA_RATE), 3) as FTA_RATE,
       ROUND(AVG(OPP_FTA_RATE), 3) as OPP_FTA_RATE
FROM (SELECT bs.team_name, 
             AVG(eFG) as eFG,
             AVG(OPP_eFG) as OPP_eFG,
             AVG(TOV_PCT) as TOV_PCT,
             AVG(OPP_TOV_PCT) as OPP_TOV_PCT,
             AVG(ORB_PCT) as ORB_PCT,
             AVG(DRB_PCT) as DRB_PCT,
             AVG(FTA_RATE) as FTA_RATE,
             AVG(OPP_FTA_RATE) as OPP_FTA_RATE
      FROM box_score bs
      WHERE game_date < '2019-03-07' AND
            ( (team_name = 'Miami Heat' AND WIN_LOSS = 'W') OR
              (team_name = 'New York Knicks' AND WIN_LOSS = 'L')
            )
     ) bs
最新问题
© www.soinside.com 2019 - 2024. All rights reserved.