从数据库获取上一个条目

Question

I'm building a news website with articles and I'm trying to show the next and previous articles at the end of each post.

The next link is working fine but the previous link always shows the first ever post. Here is the get code that I'm using for each:

$get_next_sql = "SELECT * FROM articles WHERE id > '$article_id' LIMIT 1";
$get_prev_sql = "SELECT * FROM articles WHERE id < '$article_id' LIMIT 1";

Am I missing something in the prev code?

Answer 1

You are getting only posts which have id less than current.

By default, Database is sorting with PRIMARY field and IN ASC order.

So, its always returning post with lowest id .

What you need is the post lower than current and with highest id .

So, the corrected code should be:

$get_prev_sql = "SELECT * FROM articles WHERE id < '$article_id' ORDER BY id DESC LIMIT 1";

Answer 2

$get_prev_sql = "SELECT * FROM articles WHERE id < '$article_id' ORDER BY id DESC LIMIT 1";

主键的默认顺序是ASC

Answer 3

使用此查询

select * from table_name where id < your_current_id order BY id desc limit 1