What value does id give to a $_GET?

As the PHP Manual says :

$_GETis an associative array of variables passed to the current script via URL parameters.

For example in a URL like this:

http://www.dominio.com/archivo.php?id=1&nombre=Pedro

The value of $_GETwill be an array like this:

array('id'=>1, 'nombre'=>'Pedro');

If you want to get the values ​​of GET:

$_GET["id"]; //obtienes 1
$_GET["nombre"]; //obtienes Pedro

to solve your problem

Seeing that your URL is constructed like this:

#Regla Url amigable
RewriteRule ^([a-zA-Z0-9-/]+)$ detalle.php?id=$1

It would suffice to change the value in the rule idtourl

#Regla Url amigable
RewriteRule ^([a-zA-Z0-9-/]+)$ detalle.php?url=$1

If, on the contrary, the value urlwere taken from another element, or if it was equivalent to some file through which you build friendly URLs, then you would have to modify the name of the element (for example an HTML element) or the name of the file if it were a File, Archive.

Other things aboutGET

I suppose you are going to use GETor POSTmore than once, so I allow myself to leave some indications...

When you submit HTML forms, GET will associate the values ​​using the value of the elements tag nameas the key.

Example:

<form>
  <input type="number" name="id" />
  <input type="text" name="nombre" />
</form>

If you want to match the keys that you will get via GET with the column names of your database, you only have to change the value of the tag nameif you use an HTML form, or the values ​​of the URL.

Example:

HTML form

<form action="archivo.php" method="GET">
  <input type="number" name="id_producto" placeholder="Introduzca id_producto"/>
  <input type="number" name="id_usuario"  placeholder="Introduzca id_usuario"/>
  <input type="text"   name="url"         placeholder="Introduzca url"/>
</form>

When you submit this form, what is actually produced is a URL like this:

http://www.dominio.com/archivo.php?id_usuario=1&id_producto=24890&url=example.com/registrar

So, with GETwe get an array with three keys and their three respective values, each pair (key->value) is separated by &in the URL:

• id_usuario => 1
• id_producto => 24890
• url => example.com/registrar

file.php or file that receives the data from the previous form

In the PHP file you would retrieve each value like this:

$_GET["id_producto"];
$_GET["id_usuario"];
$_GET["url"];

Notes from the PHP Manual and from experience

Some indications regarding the use of GET(which are also valid for POST):

• When the values ​​come from an HTML document, GET fetches the values ​​using the nameHTML elements tag, not the id.

• It is often used issetto verify that the searched value exists in the URL (if it exists among the posted data). For example, to find out if it id_usuariowas posted:

  if(isset($_GET['id_usuario'])) {
       //existe
  }else{
       //no existe
  }
  

  This comparison can be refined, looking not only if it exists, but also if it is not blank.

• This is a 'superglobal' or an automatic global variable. It simply means that it is a variable that is available anywhere in the script. It is not necessary to do global $variable;to access it from functions or methods.

• GET variables are passed via urldecode().

• $_POSTworks the same way and is sometimes recommended over GET, but that would be another matter.

• Never directly send fetched values ​​with GETor with POSTor any other values ​​coming from outside to database queries . Doing so would make the code vulnerable to SQL Injection, through which malicious users could take control not only of the database, but of your entire system. Those values ​​must be sent using prepared queries. There are several questions here on SO dealing with this topic.

Short answer:

Change your .htaccessto the following:

 RewriteRule ^([a-zA-Z0-9-/]+)$ detalle.php?url=$1

Long Answer:

The variables $_GETin general terms are those that are sent by the URL I would explain this but A.Cedano already took the trouble.

When you make "friendly URLs" via .htaccessor virtualhostin the same way you send parameters via GETas you can see in your.htaccess

#Regla Url amigable
RewriteRule ^([a-zA-Z0-9-/]+)$ detalle.php?id=$1

you are overriding the url and internally sending the id :

detalle.php?id=$1

If you want me to change this and receive urlin your code you should change your virtualhostor .htaccessto the following:

RewriteRule ^([a-zA-Z0-9-/]+)$ detalle.php?url=$1

What happens is that what you add in $_GET['nombre']is the name of the variable that is being sent from the Front-End to the Back-End, in some of your files that variable is being sent with the name of idand that is how you must receive it, if you want to change the name you should then change it at the time of sending and receive it phpwith the new name

I hope I have been clear in the explanation, in the same way I leave you this Link with more information about the GET variables