1

我有 5 个表类别，业务，地铁，用户，收藏夹

Category
id | category_name
-------------------
 1  | bar
 2  | cafe
 3  | lunch
 4  | dinner

Business
id | business_name | zip        | address            |metro_id
--------------------------------------------------------------
1  | sanders      | 023232      | abc1               | 1
2  | ipc          | 023232      | abc2               | 1
3  | mircleFoods  | 023232      | abc3               | 1
4  | salt         | 023232      | abc4               | 2

Metro
id | name
-------------------
1  | boston
2  | newYork


Favourites
id | user_id | business_id | metro_id | category_id
----------------------------------------------------
1  | 1       | 1           | 3         | 1
2  | 1       | 1           | 4         | 2
3  | 1       | 1           | 3         | 1
4  | 1       | 1           | 5         | 2

User
id | firstName | LastName |userName   | Password
----------------------------------------------------
1  | john   | mark   | jmark1       |123
2  | john  | mark   | jmark2        | 123
3  | john   | mark  | jmark3        | 123
4  | john   | mark  | jmark4        | 123

我一直在尝试选择一个特定城市中收藏数量最多的类别，并显示其类别最受喜爱的商家名称。

我一直希望得到结果，例如

RESULT 1{
Metro->boston
category->bar
businessName->sanders
favs->23}


RESULT 2{
Metro->boston
category->cafe
businessName->sanders
favs->333}

我尝试了许多不同的查询，但现在已经开始尝试通过分解它来实现它这里是我尝试过的一些查询

1.    SELECT c.category_name,b.business_name,COUNT(f.user_id) FROM business b, category c, favourites f
INNER JOIN business ON business.id=favourites.business_id
INNER JOIN category ON category.id=favourites.category_id
GROUP BY c.category_name,b.business_name

2.    SELECT c.category_name,(SELECT COUNT(*) FROM favourites) AS fs,b.business_name FROM(favourites f,business b,category c) GROUP BY c.category_name LIMIT 0,1

3.    SELECT f.category_id, COUNT(f.user_id) AS f FROM (favourites f,metro m)  GROUP BY category_id HAVING MAX(f.user_id)=(SELECT COUNT(user_id) FROM favourites)
4

3 回答 3

0

这应该工作

SELECT c.category_name,b.business_name,COUNT(c.id)
FROM favourites AS f
INNER JOIN business AS b ON business.id=favourites.business_id
INNER JOIN category AS c ON category.id=favourites.category_id
GROUP BY c.id
ORDER BY COUNT(c.id) DESC

这将计算每个类别中最喜欢的条目，并按计数 DESC 对其进行排序

于 2013-04-29T09:25:02.787 回答
0

试试这个：

SELECT
    b.business_name,
    m.name,
    c.category_name,
    favs
FROM (
    SELECT
        business_id,
        metro_id,
        category_id,
        COUNT(*) as favs
    FROM
        Favourites 
    WHERE
        metro_id = 1
    GROUP BY
        business_id,
        category_id
) as f
INNER JOIN Metro as m
    ON m.id = f.metro_id
INNER JOIN Business as b
    ON b.id = f.business_id
INNER JOIN Category as c
    ON c.id = f.category_id
ORDER BY
    favs
LIMIT 1

它应该显示“在特定城市中具有最高收藏数量的类别，并显示具有其类别收藏最多的企业名称。”

更新：新要求“没有属于一个企业的每个类别的最大收藏量。”

SELECT
    b.business_name,
    m.name,
    c.category_name,
    favs
FROM (
    SELECT
        category_id,
        business_id,
        metro_id,
        COUNT(*) as favs
    FROM
        Favourites 
    WHERE
        business_id = 1
    GROUP BY
        category_id,
        metro_id
    ORDER BY
        favs DESC
    LIMIT 1
) as f
INNER JOIN Metro as m
    ON m.id = f.metro_id
INNER JOIN Business as b
    ON b.id = f.business_id
INNER JOIN Category as c
    ON c.id = f.category_id
于 2013-04-29T09:26:51.830 回答
0

根据需要替换搜索。这应该通过点击正确地对业务/类别进行分组：

SELECT COUNT(f.user_id) AS hits, c.category_name, b.business_name
FROM Favourites AS f
JOIN Category AS c ON (c.id = f.category_id)
JOIN Business AS b ON (b.id = f.business_id)
JOIN Metro AS m ON (m.id = f.metro_id)
WHERE m.name="boston" AND c.category_name="bar"
GROUP BY f.business_id, f.category_id
ORDER BY hits DESC
于 2013-04-29T09:27:47.847 回答