修复了黑客 SQL where 子句 - Fix hackish SQL where clause

Fix hackish SQL where clause

本文关键字：where 子句 SQL 黑客 | 更新日期: 2023-09-27

>我有两个表，activities和activity_tours。 activities有很多activity_tours，并且与activities.id> activity_tours.activity_id有关。我编写了以下 SQL 来选择两个表中具有两个条件之一的行。

如果它有一定的activity_tours.tour_type或
活动有多个游览

该查询似乎有点黑客。有人可以帮助我提高此查询的效率吗？

SELECT SQL_CALC_FOUND_ROWS
    activities.activity_name,
    activities.image_path,
    activity_tours.tour_type
FROM
    activities
    LEFT JOIN activity_tours ON activities.id = activity_tours.activity_id
WHERE
    (
        activity_tours.tour_type != 17 OR (
            (SELECT count(*) FROM activity_tours WHERE activity_id = activities.id) > 1)
    )

SELECT a.activity_name,
    a.image_path,
    at.tour_type,
    MAX(at.tour_type != 17) AS tour_not_17,
    COUNT(*) AS tour_count
FROM activities a
INNER JOIN activity_tours at ON a.id = at.activity_id
GROUP BY a.activity_name, a.image_path
HAVING tour_not_17 OR tour_count > 1

不知道如何处理tour_type列;应该使用聚合，但我无法弄清楚是哪一个。也许你可以做GROUP_CONCAT()？