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That title is probably terrible so let me try to explain with an example

I have a table that consists of top 10 teams called _top 10. In order to select all the teams that have played a top 10 team at home I can run this query.

SELECT      g.home_team,
            IFNULL(SUM(g.home_wins), 0) AS formula 
FROM        games g
WHERE 
            away_team IN (SELECT team_id FROM _top_10) 
GROUP BY    g.home_team 
ORDER BY    formula DESC

This will return a list of all the teams that have played top 10 teams at home along with a number of home many wins against top 10 teams at home they have. What I want included in this list is all the teams that haven't played a top 10 team at home and obviously a zero for wins against top 10 teams at home. Hope this makes sense.

Here is the union code I tried in order to combine the results

SELECT      g.home_team,
            IFNULL(SUM(g.home_wins), 0) AS formula ,
            t.*
FROM        games g
INNER JOIN _top_10 AS t ON g.away_team = t.team_id

UNION

SELECT      g.home_team,
            SUM(0) AS formula ,
            t.*
FROM        games g
LEFT JOIN _top_10 AS t ON g.away_team = t.team_id
WHERE t.team_id IS NULL
GROUP BY    g.home_team 
ORDER BY    formula DESC;

UPDATE

I've put everything together and I'm getting

Error Code: 1248. Every derived table must have its own alias

Here is my final query

SELECT     IF(@last_ranking <> formula, @current_rankings := @current_rankings + 1, @current_rankings)  AS rank, 
            @last_ranking := formula, 
            prequery.team, 
            prequery.formula
FROM        (select @current_rankings := 0) sqlvars, 
            (SELECT    team, 
                        SUM(score) formula 
            FROM (SELECT     g.home_team, 
                            SUM(CASE WHEN t.team_id IS NULL THEN 0 ELSE g.home_wins END) AS formula 
            FROM            games g LEFT JOIN 
                        _top_10 AS t ON g.away_team = t.team_id 
            WHERE       
                        g.season = 2012 AND 
                        g.completed = 1 
        UNION ALL SELECT     g.away_team, 
                        SUM(CASE WHEN t2.team_id IS NULL THEN 0 ELSE g.away_wins END) AS formula 
            FROM        games g LEFT JOIN 
                        _top_10 AS t2 ON g.home_team = t2.team_id 
            WHERE      
                        g.season = 2012 AND 
                        g.completed = 1), 
                            (SELECT @current_rankings := 0, @last_ranking := 0) r 
                GROUP BY team ORDER BY formula DESC ) prequery;

Any help would be greatly appreciated

4

1 回答 1

1

JOIN表而不是IN谓词：

SELECT      g.home_team,
            IFNULL(SUM(g.home_wins), 0) AS formula ,
            t.*
FROM        games g
INNER JOIN _top_10 AS t ON g.away_team = t.team_id
GROUP BY    g.home_team 
ORDER BY    formula DESC;

要获得那些没有在主场打过前 10 名球队的球队，请使用LEFT JOINwith WHERE t.team_id IS NULL：

SELECT      g.home_team,
            IFNULL(SUM(g.home_wins), 0) AS formula ,
            t.*
FROM        games g
LEFT JOIN _top_10 AS t ON g.away_team = t.team_id
WHERE t.team_id IS NULL
GROUP BY    g.home_team 
ORDER BY    formula DESC;

更新：

您可以使用一个查询来做到这一点：

SELECT 
  g.home_team, 
  SUM(CASE WHEN t.team_id IS NULL THEN 0 ELSE g.home_winsEND) AS formula,
  ...
FROM games g 
LEFT JOIN _top_10 AS t ON g.away_team = t.team_id 
GROUP BY g.home_team, ...;
于 2013-03-19T19:55:54.293 回答