How to clear table data in php

In our projects, we often need to clear data on certain tables in order to refill the data for testing or other operations. If you delete them one by one manually, it will be very time-consuming and not efficient enough. At this time, using SQL statements to clear table data is a good choice. For PHP, it provides a very convenient method to execute SQL statements. Let's introduce how PHP clears table data.

First, we need to clear the table data explicitly, that is, delete all records in the table. Then you need to use the DELETE statement to operate. The syntax is as follows:

DELETE FROM table_name

Among them, table_name represents the name of the table where data needs to be deleted, that is, the name of the table we want to clear.

So how to execute this statement in php? You can use the mysql_query() function. This function is used to execute a mysql query statement and return the query results. The function format is as follows:

mysql_query( $query, $connection );

Among them, the $query parameter represents the SQL statement to be executed, and the $connection parameter represents the database link. If the query is executed successfully, the function will return true, otherwise it will return false. We can use this function to execute the DELETE statement to clear the data. The sample code is as follows:

<?php
    // 数据库连接参数
    $host = 'localhost';  // 主机名
    $user = 'root';       // 用户名
    $password = '';       // 密码
    $database = 'test';   // 数据库名
    
    // 创建数据库连接
    $connection = mysql_connect( $host, $user, $password );
    
    // 选择数据库
    mysql_select_db( $database );
    
    // 执行DELETE语句
    $query = "DELETE FROM table_name";
    $result = mysql_query( $query, $connection );
    
    // 判断是否删除成功
    if ( $result ) {
        echo "删除成功";
    } else {
        echo "删除失败";
    }
?>

In practical applications, we can also add restrictions to the query statement, that is, delete data in the table based on certain conditions. For example:

DELETE FROM table_name WHERE id > 100

The above SQL statement means to delete records with id greater than 100 in the table. In the same way, executing this statement in PHP can also be achieved through the mysql_query() function. The sample code is as follows:

<?php
    // 数据库连接参数
    $host = 'localhost';  // 主机名
    $user = 'root';       // 用户名
    $password = '';       // 密码
    $database = 'test';   // 数据库名
    
    // 创建数据库连接
    $connection = mysql_connect( $host, $user, $password );
    
    // 选择数据库
    mysql_select_db( $database );
    
    // 执行DELETE语句
    $query = "DELETE FROM table_name WHERE id > 100";
    $result = mysql_query( $query, $connection );
    
    // 判断是否删除成功
    if ( $result ) {
        echo "删除成功";
    } else {
        echo "删除失败";
    }
?>

The above is the SQL operation method for clearing table data in PHP. This way we can perform data cleaning operations faster and more efficiently.

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