如何按日期返回最後5行

Question

如何根據從最早到最新排序的表格返回最近5行（按日期）。

I.E.

$query = mysqli_query($connect,"SELECT * FROM posts 
WHERE postid like '$topic_id' 
ORDER BY postdate DESC LIMIT 5"); 

返回：

reply 10 
reply 9 
reply 8 
reply 7 
reply 6 

和：

$query = mysqli_query($connect,"SELECT * FROM posts 
WHERE postid like '$topic_id' 
ORDER BY postdate ASC LIMIT 5"); 

返回：

reply 1 
reply 2 
reply 3 
reply 4 
reply 5 

---

如何退還？

reply 6 
reply 7 
reply 8 
reply 9 
reply 10 

Answer 1

使用子查詢獲取最近的行，然後在主查詢中以其他方式對其進行排序。

SELECT * 
FROM (SELECT * FROM posts 
     WHERE postid like '$topic_id' 
     ORDER BY postdate DESC LIMIT 5) x 
ORDER BY postdate ASC 

要回答這個不可避免的問題，x是子查詢的別名，因爲MySQL需要的所有子查詢中加入與別名命名。