dongxiong4571 2016-10-13 13:00
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使用php删除mysql中id最高的行

I'm working on a really simple minichat program (php/mysql) which displays the last 10 messages.

I wanted to add a button to delete the last message (using a form, leading to a php file like the one under).

I'm really a beginner with php and mysql so, I don't understand why it doesn't work.

Follows my code:

<?php 
    // Create connection
    $cn = new mysqli("localhost","root","","test");

    // Check connection
    if($cn->connect_error)
    {
        echo "Connection failed : " . $cn->connect_error;
    }

    $sql = "DELETE FROM `minichat` WHERE `minichat`.`id` = ('SELECT MAX(`id`) FROM `minichat`')";

    if($cn->query($sql) === TRUE){
            echo "Deleted succesfully";
    }
    else
    {
        echo "Error deleting record: " . $cn->error;
    }

    //header('Location: connexion.php');
?>
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3条回答 默认 最新

  • dongshendi3599 2016-10-13 13:21
    关注

    According to the manual on DELETE Syntax:

    Subqueries

    You cannot delete from a table and select from the same table in a subquery.

    So instead you should do something like:

    DELETE FROM minichat ORDER BY id DESC LIMIT 1
    

    And you probably want a condition to make sure a user can only delete his / her own comment..

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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