在 mysql 中没有获得所需的输出

Question

我正在 mysql 中触发查询，但没有获得所需的输出。 这是代码：

select team_name,
       sum(semis.points+final.points) as final_points 
from semis 
inner join final on semis.sid=final.sid 
inner join teams on teams.tid=semis.tid 
group by semis.tid 
   union 
select team_name,
       semis.Points 
from semis 
inner join teams on semis.tid=teams.tid 
left join final on semis.sid=final.sid 
where final.sid is null;

输出：

+-----------------------+--------------+
| team_name             | final_points |
+-----------------------+--------------+
| BioTech & BioChem     |            7 |
| Chemistry             |            7 |
| Botany & Zoology      |            7 |
| Physics & Electronics |           17 |
| BCA                   |           19 |
| BCOM                  |           11 |
| Gujarati              |           10 |
| English               |           10 |
| Economics             |           20 |
| BCOM                  |            3 |
| Chemistry             |            3 |
| English               |            3 |
+-----------------------+--------------+

我想获取的结果

+-----------------------+--------------+
| team_name             | final_points |
+-----------------------+--------------+
| BioTech & BioChem     |            7 |
| Chemistry             |           10 |
| Botany & Zoology      |            7 |
| Physics & Electronics |           17 |
| BCA                   |           19 |
| BCOM                  |           14 |
| Gujarati              |           10 |
| English               |           13 |
| Economics             |           20 |
+-----------------------+--------------+

将最后 3 个值添加到 english,bcom,chemistry 将其增加 3 并使其总数为 BCOM: 14, Chemistry:10 , English: 13

Answer 1

从您发布的示例数据和预期结果来看，您似乎可以在没有UNION情况下完成它，方法是 left final.points final并使用coalesce() for final.points ：

select team_name, sum(semis.points + coalesce(final.points, 0)) as final_points 
from semis 
inner join teams on teams.tid=semis.tid 
left join final on semis.sid=final.sid 
group by semis.tid