-1
基礎數據模型:http://i.imgur.com/WKWBDd8.jpgMYSQL MULTI JOINS with COUNTS
嗨,thx求救!
我希望做一個查詢來獲取的問題數(計數),並從課程答案的數目,
SELECT
courses.name,
courses.description,
courses.digest,
courses.views,
categories.icon,
COUNT(answers.id),
COUNT(problems.id)
FROM
courses
INNER JOIN
topics ON topics.id = courses.topics_id
INNER JOIN
categories ON categories.id = topics.categories_id
LEFT JOIN
problems ON problems.courses_id = courses.id
LEFT JOIN
answers ON answers.problems_id = problems_id
WHERE
courses.accounts_id = 1
GROUP BY courses.id
但是,這是行不通的任何想法?
THX
是錯誤信息還是意外行爲分類?如果沒有,請與我們分享。 – Shadow
可能是一個拼寫錯誤,但在你最後一次加入時,你正在執行'answers.problems_id = problems_id'這是正確的嗎?應該是problems.id嗎? – Matt