I can't delete fields in a mysql database - php

Question

I need to delete to generate a form to select in checkboxes which users I want to delete from the database. To search the users and generate the form I use this code:
<?php
$con = new mysqli('localhost', 'root', '', 'prueba');
$busqueda ="";
$busqueda=$_POST['busqueda'] ;
// funcion para convertir el contenido de un array en un string
function makestring($array)
{
$outval = '';
if (is_array($array)) {
foreach($array as $key=>$value)
{
if(is_array($value))
{
$outval = makestring($value);
}
else
{
$outval = $value;
}
}
}
return $outval;
}
if ($busqueda!=""){
$busca = mysqli_query($con, " SELECT usuario FROM usuarios WHERE
usuario LIKE '%$busqueda%'");
echo "<form action='borrar.php' method='post' enctype='multipart/form-data'>";
while ($array= mysqli_fetch_array($busca)){
$user=makestring($array);
echo"Usuario: <input type='checkbox' name='borrar_usuario[]' value='$user' />$user<br/>";
}
echo " <input type='submit' name='boton' value='eliminar' />";
echo "</form>";
}
$all =$_POST['todos'] ;
if ($all=='borrar_todos'){
$busca = mysqli_query($con, "select usuario from usuarios ");
echo "<form action='borrar.php' method='post' enctype='multipart/form-data'>";
while ($f = mysqli_fetch_array($busca)){
$user=makestring($f);
echo "Usuario: <input type='checkbox' name='borrar_usuario[]' value='$user' />$user<br/>";
}
echo " <input type='submit' name='boton' value='eliminar' />";
echo "</form>";
}
?>
I use this code to collect the data from the forms with this code:
<?php
$con = new mysqli('localhost', 'root', '', 'prueba');
if(isset($_REQUEST["borrar_usuario"])) {
$del_user = $_POST["borrar_usuario"];
$mensaje = "¿Está seguro que quiere eliminar el usuario <b>$row[usuarioNombre]</b>?";
}
// mostramos el mensage
echo $mensaje;
mysqli_query($con, "delete usuario, password, descripcion from usuarios
where usuario in like '$del_user'");
echo "usuario borrado";
header('refresh: 3; url= exito.php');
?>
But it doesn't delete anything in the database. Any help please?

Answer 1

DELETE deletes the entire row from the database. You question feels like you need to Empty some specific fields. Try the following Code
mysqli_query($con, "UPDATE usuarios SET usuario = null, password =null,
descripcion=null where usuario like '$del_user'");

Answer 2

If you want to empty a field or fields, you need to use update usuarios set usuario = '', password = '', descripcion = '' where usuario like '$del_user'"

Answer 3

Try this as the delete query
"delete from usuarios where usuario = '$del_user'"

Answer 4

Use this if you delete one user at the time:
delete from usuarios where usuario = '$del_user'
or this if you delete more users and have ids in comma(,) delimited list
delete from usuarios where usuario in ('$del_user')