How to check whether a field exists in php

How to implement the PHP query field: 1. Create a PHP sample file; 2. Connect to the database; 3. Query a certain value through the "select * from" statement; 4. Use "if (!mysql_num_rows( $result)){...}else{...}" statement can be used to determine whether the value exists.

The operating environment of this tutorial: Windows 7 system, PHP version 8.1, Dell G3 computer.

How to check whether a field exists in php?

php Query the database table to determine whether a certain value exists

The code is as follows:

<?php  
$sql="select * from checklist where game_id=$gid and task=&#39;$task&#39; and status=&#39;$status&#39;";  
$result=mysql_query($sql);  
$row = mysql_fetch_array($result, MYSQL_ASSOC);  
    if (!mysql_num_rows($result))  
        {  
            echo "record doesn&#39;t exist~~~~~!!!!!!";  
        }  
    else  
        {             // echo mysql_num_rows($result)."\n";  
            echo $row[&#39;game_id&#39;];  
            echo $row[&#39;task&#39;];  
        }  
?>

Extended information

General steps to access MySql

1) Connect to MySql server

Use the mysql_connect() function to establish a connection with the MySql server.

2) Select the MySql database

Use the mysql_select_db() function to select the database on the MySql server and establish a connection with the database.

3) Execute SQL statements

Use the mysql_query() function to execute SQL statements. (Including adding, deleting, modifying, querying, and displaying)

4) Close the result set

Use mysql_free_result($result) to close the result set to release resources.

Recommended learning: "PHP Video Tutorial"

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