Question

我试图从5个类别的SQL中的两个连接表中访问详细信息，其中一个我需要运行COUNT函数。我能够访问细节，直到我运行计数功能，之后我只能使用一个结果。我也尝试使用COUNT（*）作为... - 但这没有用。代码如下：

SELECT name, location, grade_1996, COUNT(voter_id)
FROM votes
JOIN congress_members
ON congress_members.id=politician_id
WHERE grade_current < 9;

请帮助，谢谢。

Answer 1

您需要group by。也许这就是你想要的：

SELECT name, location, grade_1996, COUNT(voter_id)
FROM votes JOIN
     congress_members
     ON congress_members.id=politician_id
WHERE grade_current < 9
GROUP BY name, location, grade_1996;

Answer 2

您缺少GROUP BY子句：

select name,
    location,
    grade_1996,
    COUNT(voter_id)
from votes
join congress_members on congress_members.id = politician_id
where grade_current < 9
group by name,
    location,
    grade_1996;

在SQLite3中使用COUNT

2 个答案: