如何从数据库中获取特定行？

Question

I'm creating simple website and need to get specific column from database. I need to get only last 5th column from database to be displayed, and I'm stuck here.

This code I tried:

SELECT * FROM `post` ORDER BY `post_date` LIMIT 4, 5

But with this code on my page I get all rows from last 5th column to last 10 and I don't need that I need just to display last inserted 5th column.

My full code looks like this:

class Second {
        public function second_post(){
            global $pdo;

            $query = $pdo->prepare('SELECT * FROM `post` ORDER BY `post_date` LIMIT 4, 5');
            $query->execute();

            return $query->fetchAll(PDO::FETCH_ASSOC);
        }

        public function fetch_data($pid){
            global $pdo;

            $query = $pdo->prepare('SELECT * FROM `post` ORDER BY `post_date` LIMIT 4, 5');
            $query->BindValue(1,$pid);
            $query->execute();

            return $query->fetch();
        }
    }

$sec = new Second;
    $check = new Second;
    $secs = $sec->second_post();

Answer 1

Use SELECT * FROM post ORDER BY post_date LIMIT 1 OFFSET 4

The second parameter after LIMIT defines the offset. This way you can return only 1 record and start on record 5 (OFFSET 4).

You can also use SELECT * FROM post ORDER BY post_date LIMIT 4, 1 , the result will be the same. Notice that the numbers are reversed when you use a comma.

Answer 2

Use DESC LIMIT ?

So code must be for last 8 inserted column's:

$query = $pdo->prepare('SELECT * FROM `post` ORDER BY `post_id` DESC LIMIT 8');

This code display last inserted columns from database.

Answer 3

您可以直接获得第5列，例如

SELECT COLUMN_NAME -> FROM post;

Answer 4

Your Query is SELECT * FROM post ORDER BY post_date LIMIT 4, 5

as you want only 1 row, so limit should be 1 .

now you want last inserted so you need to use DESC

Just use this query, and you are done,

SELECT * FROM post ORDER BY post_date DESC LIMIT 1, 5