如何仅回显一个参数并集所有参数 - How to echo only one parameter with union all

How to echo only one parameter with union all

本文关键字：参数一个何仅回 | 更新日期: 2023-09-27

我必须数据库表。我想打印两个表中的所有名称，如果出现多个名称，则仅打印一次并将其设置为红色。我的PHP：

<?php
    include 'verification/verify_form_details.php';
    $result5 = getUsers();
    if (!$result5) {
        die('Invalid query: ' . mysqli_error());
    }   
    while($row5 = mysqli_fetch_array($result5))
    {  
        $username = $row5['username'] ;
        echo '<ul>';    
        echo"<li>". $username ."</li>";
        echo '</ul>';   
    }           
?>

还有我的查询：

function getUsers()
{
    global $con;
    $sql = "SELECT username FROM `user_project` 
            UNION ALL 
            SELECT username FROM `user`";
    return mysqli_query($con,$sql); 
}

我怎样才能做到这一点？

将查询修改为按用户名分组

    $sql = "SELECT username FROM 
            (
            SELECT username FROM `user_project` 
            UNION ALL 
            SELECT username FROM `user`
            )
            GROUP BY username";

另外，如果您想获得出现次数，以便您可以使红色具有多次出现的红色

$sql = "SELECT username, count(username) FROM 
                (
                SELECT username FROM `user_project` 
                UNION ALL 
                SELECT username FROM `user`
                )
                GROUP BY username";

$sql = "SELECT username FROM 
        (
        SELECT username FROM `user_project` 
        UNION ALL 
        SELECT username FROM `user`
        )
        GROUP BY username";

为此添加"独特">