Group query to get specific order

Question

I use this query to populate my gallery:

  var queryGallery = "$select=Title,Description,Enlace,EncodedAbsUrl,Categoria/Title&$expand=Categoria/Title";


$.ajax({
url: url + "/_api/web/lists/getbytitle('" + listname + "')/items?$top=1000&" + queryGallery, 
//url: url + "/_api/web/lists/getbycategory('Office'),

method: "GET",
headers: { "Accept": "application/json; odata=verbose" },
success: function (data) {
    completeGalleryContent(data, target, eng);
},
error: function (data) {
    failureGalleryContent(data, target);
}
});
}

The problem is that I don´t know why first take one image of each category and after that get all images of one categorie, for example I have this categories

Services, Home, Office

In my first row of images I get:

firstimageServices
firstimageHome
firstimageOffice
secondimageOffice
thirdimageOffice
etc... 

But I want to group all by categorie, so it will be:

firstimageServices
secondimageServices
thirdimageServices
fourimageServices
etc...
firstimageHome
secondimageHome
thirdimageHome
fourimageHome
etc...
firstimageOffice
secondimageOffice
thirdimageOffice
fourimageOffice
etc..

How can I do in my query to group it? Regards!

Note: I look something of interest in these link msdn but how can I apply it in my query to sort by "Categoria"

Answer 1

You should add a '&$', not just '$' before the orderby clause, like this:

"$select=Title,Description,Enlace,EncodedAbsUrl,Categoria/Title&$expand=Categori‌​a/Title&$orderby=Categoria,Title asc";