不能通过

select sum(total) from (
(select sum(team1_score) as total from country,match_results where country_name=team1 group by country_name as s1) 
UNION ALL 
(select sum(team2_score) as total from country,match_results where country_name=team2 group by country_name as s2) 
);

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2017-09-25 nikhil kekan

从

select sum(total) from (
    select sum(team1_score) as total 
    from country,match_results 
    where country_name=team1 
    group by country_name 
    UNION ALL 
    select sum(team2_score) 
    from country,match_results 
    where country_name=team2 
    group by country_name 
) T

删除在选择第二别名和别名为组和assigna真名的子查询，您应该使用显式的内部连接

select sum(total) from (
    select sum(team1_score) as total 
    from country 
    inner join match_results on country.country_name=team1 and 
    match_results.team1=team1 
    group by country_name 
UNION ALL 
    select sum(team2_score) 
    from country 
    inner join match_results on country.country_name=team2 and 
    match_results.team2=team2 
    group by country_name 
) T

来源

2017-09-25 18:30:19 scaisEdge

非常感谢scaisEdge，两种解决方案现在工作得很好。但在第二个建议使用内部连接，你可以解释为什么使用两个条件 country.country_name = team2和match_results.team2 = team2？ –

是相同的..我hav eopted这个，因为更容易理解，但你也可以使用国家内部联接match_results country.country_name = match_results.country_name和country.country_name = team1 ...是一样的...使用传递属性或不结果不改变 – scaisEdge

@nikhilkekan好，如果我的回答是正确的请标记为接受...看到这里如何 http://meta.stackexchange.com/questions/5234/how-does -accepting-的回答工作 – scaisEdge

尝试移除即别名as s1和as s2

来源

2017-09-25 18:26:28

试过没有工作，我还是谢谢你 –

别名应是子查询外，使用组中的SQL两个查询的结合; MySQL可能认为你试图（毫无意义地）混淆了分组标准。

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2017-09-25 18:29:50 Uueerdo

尝试没有工作，无论如何谢谢 –

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