Question

我的表是：

tbl_activity（id，name）
tbl_activity_package（id，activity_id，name）
tbl_activity_package_address（id，activity_package_id，district）

用户给出一个区域，然后返回该区域内发生的活动列表。活动可以有多个分区，因此我必须在GROUP_CONCAT()之后将其退回。

SELECT a.name, ap.name
FROM (
    SELECT apa_inner.activity_package_id AS activity_package_id
    FROM tbl_activity_package_address AS apa_inner
    WHERE district = 'Beja'
) AS apa
INNER JOIN (
    SELECT ap_inner.id, ap_inner.name, ap_inner.activity_id
    FROM tbl_activity_package_address AS apa_inner
    INNER JOIN tbl_activity_package AS ap_inner ON ap_inner.id = apa.activity_package_id
) AS ap ON apa.activity_package_id = ap.id
INNER JOIN tbl_activity AS a ON a.id = ap.activity_id

这给了我错误：＆＃34;未知列＆＃39; apa.activity_package_id＆＃39;在＆＃39; on＆＃39;条款＆＃34;

SELECT a.name, ap.name
FROM (
    SELECT id, activity_package_id
    FROM tbl_activity_package_address AS apa_inner
    WHERE district = 'Beja'
) AS apa
INNER JOIN (
    SELECT ap_inner.id AS id, ap_inner.name, ap_inner.activity_id
        FROM tbl_activity_package_address AS apa_inner
        INNER JOIN tbl_activity_package AS ap_inner ON ap_inner.id = apa_inner.activity_package_id
        WHERE apa_inner.id = apa.id
) AS ap ON apa.activity_package_id = ap.id
INNER JOIN tbl_activity AS a ON a.id = ap.activity_id

这给了我错误：＆＃34;未知列＆＃39; apa.id＆＃39;在where子句＆＃34; 。

Answer 1

旧答案

在您的第二个子选择中，您使用别名apa_inner和ap_inner，所以

SELECT a.name, ap.name
FROM (
    SELECT apa_inner.activity_package_id AS activity_package_id
    FROM tbl_activity_package_address AS apa_inner
    WHERE district = 'Beja'
) AS apa
INNER JOIN (
    SELECT ap_inner.id AS id
        FROM tbl_activity_package_address AS apa_inner
        INNER JOIN tbl_activity_package AS ap_inner ON ap_inner.id = apa_inner.activity_package_id
) AS ap ON apa.activity_package_id = ap.id
INNER JOIN tbl_activity AS a ON a.id = ap.activity_id

应该修复错误。但你真的需要那些子选择吗？我相信你可以简化这个查询。

新答案

好的

tbl_activity（id，name） tbl_activity_package（id，activity_id，name） tbl_activity_package_address（id，activity_package_id，district）

并且结果应该产生所有活动，这些活动包含在某个区域中具有包地址的任何包，其中包含活动所涵盖的所有地区的列表。

此查询将执行此操作

SELECT
    a.name,
    GROUP_CONCAT(DISTINCT apa.district ORDER BY apa_district) AS distritos
FROM
    tbl_activity a
INNER JOIN
    tbl_activity_package ap
ON
    a.id = ap.activity_id
INNER JOIN
    tbl_activity_package_address apa
ON
    ap.id = apa.activity_package_id 
WHERE a.id IN (
    SELECT 
        ap_inner.activity_id
    FROM
        tbl_activity_package AS ap_inner
    INNER JOIN
        tbl_activity_package_id apa_inner
    ON
        ap_inner.id = apa_inner.activity_package_id 
    WHERE    
        apa_inner.district = 'Beja'
)       
GROUP BY 
    a.name

Answer 2

试试这个

SELECT apa.activity_package_id AS activity_package_id,ap.id, ap.name, ap.activity_id
FROM tbl_activity AS a 
INNER JOIN tbl_activity_package AS ap ON a.id = ap.activity_id 
INNER JOIN tbl_activity_package_address AS apa ON apa.activity_package_id = ap.id
WHERE district = 'Beja'

来自另一个subselect的subselect字段有什么问题？

2 个答案: