IN operator working with multivalues

I have this select:

<select id="select_filtro_tipo_documento" class="form-control">
 <option value="0,1,2,3" selected="true">Tutti i documenti</option>
 <option value="0">Ricevute di vendita</option>
 <option value="1">Fatture di vendita</option>
 <option value="2">Documento di trasporto</option>
 <option value="3">Nota di credito</option>
</select>

and I have this Server Action:

If I select value 0 or 1 or 2 or 3 it works, but if I select value 0,1,2,3 “Tutti i documenti” I don’t show all documents

Why?

You need to convert the list into an array before using with ‘IN’. There is a a thread here about this.