Question

表主题：

+--------+----+
|  name  | id |
+--------|----+
| apple  | 3  |
| banana | 1  |
| tree   | 4  |
| horse  | 6  |
| bird   | 7  |
| raq    | 2  |
+--------+----+

所以我尝试这样的输出（例如，如果我的$id_subject = 4，我的下一行必须是5 -6 7-1 ....）

+--------+----+
|  name  | id |
+--------+----+
| tree   | 4  |
| horse  | 6  |
| bird   | 7  |
| banana | 1  |
| raq    | 2  |
| apple  | 3  |
+--------+----+

我的查询：

select subject_url,subjects.id
    from students_group
    left join teacher_group on teacher_group.group_school_id = students_group.group_id
    left join subjects on teacher_group.subject_id = subjects.id
    where   students_group.user_id = 83
    ORDER BY subjects.id = 5 desc

但我得到了这个输出：

+--------+----+
|  name  | id |
+--------+----+
| tree   | 4  |
| apple  | 3  |
| banana | 1  |
| horse  | 6  |
| bird   | 7  |
| raq    | 2  |
+--------+----+

如何让它按预期工作？

Answer 1

尝试

ORDER BY subjects.id＆gt; = 5 desc，subjects.id asc

“subjects.id＆gt; = 5”将返回1或0，因此其行为true的行将首先出现，在这些行中，它们将按ID递增排序

Answer 2

select subject_url,subjects.id
from students_group
left join teacher_group on teacher_group.group_school_id = students_group.group_id
left join subjects on teacher_group.subject_id = subjects.id
where   students_group.user_id = 83
ORDER BY 
     (subjects.id >= 4) DESC
   ,  subjects.id       ASC

Answer 3

ORDER BY 
if (subjects.id=$id_subject, -1,
  if (subjects.id>$id_subject, 0, 1)
), subjects.id

按特定数字查询订单后，按升序排序

3 个答案: