SQL 查询中选择的语法 [英] Syntax for Select in SQL Query

问题描述

我有一个带有下表的 sqlite 数据库:

I have an sqlite database with the following table:

CREATE TABLE games (name text, date text, winloss int, gameid int, pointsfor int, pointsagainst int);

两个示例记录如下:

Anna A, 7/12/13, 0, 345, 56, 28
Barley B, 7/12/13, 1, 345, 28, 56

(Barley 的球队输了，Anna 赢了.每场比赛每队都有几名球员.)我想创建一个查询，该查询将返回在一个球队中有 x 名球员而在另一支球队中有 y 名球员的所有比赛，加上累积那些游戏的结果.

(Barley's team lost, and Anna's won. Each game has several players on each team.) I want to create a query that will return all the games that had x players on one team and y players on another, plus the cumulative result of those games.

我知道如何使用 perl 和 csv 文件执行此操作，并且我相信我可以对 dbi 接口使用相同的方法.但是，我想了解如何仅使用 SQL 查询来创建此报告.我是 SQL 的新手，我怀疑该解决方案可能涉及使用 CASE WHEN 或 JOIN 对表进行透视以创建新表；但我不知道该怎么做.

I know how to do this using perl and a csv file, and I believe that I could use the same method with the dbi interface. I want to learn how to create this report using only SQL queries, however. I am a newcomer to SQL, and I suspect the solution may involve pivoting the table using CASE WHEN or JOIN to create a new table; but I can't see how to do it.

此查询将返回玩家在同一支球队并赢得(或输掉，取决于 winloss 的值)的所有比赛:

This query will return all the games where the players were on the same team and won (or lost, depending on the value of winloss):

select gameid,date from games
where name in ('Anna A', 'Barley B') and winloss=1 
group by gameid 
having count(*)>1;

但我不知道如何概括该查询以返回与另一支球队的球员的比赛.

But I don't know how to generalize that query to return games with players on the other team.

推荐答案

这将为您提供 A 和 B 战胜 C、D 和 E 的一场或多场比赛的所有台词.

This will give you all the lines for the game or games where A and B won versus C, D and E.

select * 
from games 
where gameid in    
    (select gameid from games
        where name in ('Anna A', 'Barley B') and winloss=1 
        group by gameid 
        having count(*) = 2
    intersect
     select gameid from games
        where name in ('Charly C', 'Dave D', 'Ed E') and winloss = 0 
        group by gameid 
        having count(*) = 3) ;

或者，您可以使用:

select *
from games where gameid in (
    select gameid from games where name = 'Anna A'   and winloss = 1   intersect
    select gameid from games where name = 'Barley B' and winloss = 1   intersect 
    select gameid from games where name = 'Charly C'   and winloss = 0 intersect
    select gameid from games where name = 'Dave D' and winloss = 0     intersect
    select gameid from games where name = 'Ed E' and winloss = 0
    ) ;

哪个最适合你.

然后您可以添加 sum 和 group by 以获得累积结果.

You can then add sum and group by to get cumulative results.

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