Index: resources/js/xwiki/table/livetable.js
===================================================================
--- resources/js/xwiki/table/livetable.js	(revision 27358)
+++ resources/js/xwiki/table/livetable.js	(working copy)
@@ -39,7 +39,7 @@
     if (!options) {
       var options = {};
     }
-	 
+     
     // id of the root element that encloses this livetable
     this.domNodeName = domNodeName;
 
@@ -54,6 +54,9 @@
     // Array of nodes under which pagination for this livetable will be displayed.
     this.paginationNodes = options.paginationNodes || $(this.domNodeName).select(".xwiki-livetable-pagination");
 
+    // Remember which fields should send back distinct value with JSON results
+    this.distinct = options.distinct || [];
+
     if (typeof options == "undefined") {
        options = {};
     }
@@ -65,7 +68,7 @@
     if (typeof this.paginationNodes != "undefined") {
        this.paginator = new LiveTablePagination(this, this.paginationNodes, options.maxPages || 10);
     }
-	// Initialize filters
+    // Initialize filters
     if (this.filtersNode) {
       this.filter = new LiveTableFilter(this, this.filtersNode);
     }
@@ -85,11 +88,12 @@
     this.recvReqNo = 0;
 
     this.observeSortableColumns();   
- 
+
     // Show initial rows
     this.showRows(1, this.limit);
   },
 
+
   /**
     * Initializes an AJAX request for retrieving some table data. Uses two ranges, one defines the
     * range that must be retrieved from the server, and one defines the range that should be
@@ -117,6 +121,12 @@
        });
     }
 
+    if (typeof this.distinct != "undefined" && this.distinct.length > 0) {
+       this.distinct.each(function(field) {
+          url += ("&distinct=" + field);
+       });
+    }
+
     url += this.getSortURLFragment();
 
     var self = this;
@@ -145,11 +155,22 @@
         }
 
         self.updateFetchedRows(res);
+        self.updateDistinctFilters(res);
         self.displayRows(displayOffset, displayLimit);
       }
     });
   },
 
+  updateDistinctFilters: function(json)
+  {
+    for (var i=0; i<this.distinct.length;i++) {
+      var expectedName = "distinct_" + this.distinct[i].replace("\.", "_");
+      if (typeof json[expectedName] != "undefined") {
+        this.filter.updateFilter(this.distinct[i], json[expectedName]);
+      }
+    }
+  },
+
   /**
     * Add/refresh items to the cache of fetched data.
     * @param json Returned data from the server, as a parsed JSON object.
@@ -213,6 +234,7 @@
   showRows: function(offset, limit)
   {
     this.lastoffset = offset;
+
     // This is some debugging string.
     var buff  = 'request to display rows '+offset+' to '+(offset+limit)+' <br />\n';
 
@@ -474,6 +496,27 @@
     }
   },
 
+  updateFilter: function(filterName, values)
+  {
+     var filterInput = this.filterNode.down("select[name='" + filterName + "']");
+     var previouslySelected = filterInput.value;
+     if (typeof filterInput != "undefined") {
+         var tdContainer = filterInput.up('td');
+         var select = new Element("select", {'name': filterName, 'class':'distinct'});
+         select.insert(new Element("option", {'value':''}).update('none'));
+         for (var i=0;i<values.length;i++)
+         {
+           var option = new Element("option", {'value' : values[i]}).update(values[i]);
+           if (option.value == previouslySelected) {
+             option.selected = "selected";
+           }
+           select.insert(option)
+         }
+         Event.observe(select, 'change', this.makeRefreshHandler(this));
+         $(filterInput).replace(select);
+     }
+  },
+
   attachEventHandlers: function()
   {
     var inputs = this.filterNode.getElementsByTagName('input');
@@ -590,7 +633,7 @@
     */
    updateTagCloud: function(tags, matchingTags) {
       if (!this.hasTags && tags.length > 0) {
-        this.tags = tags;	 
+        this.tags = tags;    
         this.map = this.buildPopularityMap(this.tags);
         this.hasTags = true;
         this.domNode.removeClassName("hidden");
Index: templates/macros.vm
===================================================================
--- templates/macros.vm	(revision 27358)
+++ templates/macros.vm	(working copy)
@@ -1557,7 +1557,7 @@
       <div>
         <div class="xwiki-livetable-tagcloud-container">
           <h2>$msg.get("xe.livetable.tags.help")
-	        <span>$msg.get("xe.livetable.tags.help.cancel")</span>
+            <span>$msg.get("xe.livetable.tags.help.cancel")</span>
           </h2>
           <div class="xwiki-livetable-tagcloud"></div>
         </div>
@@ -1587,6 +1587,7 @@
         <table class="xwiki-livetable-display">
           <thead class="xwiki-livetable-display-header">
             <tr>
+            #set($distinct = $util.arrayList)
             #foreach($colname in $collist)
               #set($colprop = $colprops.get($colname))
               #if(("$!colprop.filterable" == "" || $colprop.filterable != false) && "$!colname" != "_actions")
@@ -1646,6 +1647,16 @@
                 #end
                 </select>
                 </td>
+              #elseif("$!colprop.type" == "distinct" && $isFilterable)
+                ## First, add the field to the list of distinct fields (they will be passed later on to
+                ## the javascript livetable object, so that they can be sent as AJAX parameters to the JSON source)
+                #set($discard = $distinct.add($colname))
+                <td class="xwiki-livetable-display-header-filter field-distinct-filter">
+                  ## This input field will be replaced dynamically by a select list as soon as a livetable AJAX request
+                  ## returns results.
+                  ## It is need to keep a reference on the column name (attribute "name" of the input)
+                  <select name="${colname}" type="text" id="xwiki-livetable-${divid}-filter-${velocityCount}"></select>
+                </td>
               #elseif( ("$!colprop.type"=="text"||"$!colprop.type"=="number") && $isFilterable)
                 <td class="xwiki-livetable-display-header-filter"><input id="xwiki-livetable-${divid}-filter-${velocityCount}" name="${colname}" type="text" #if("!$colprop.size"!="") size="${colprop.size}" title="$msg.get('xe.livetable.filters.title', [$msg.get("${transprefix}${colname}")])"#end /></td>
               #elseif("$!colprop.type"=="hidden")
@@ -1678,9 +1689,17 @@
   <script type="text/javascript">
   //<![CDATA[
   #if($callback)
-    $jsName = new XWiki.widgets.LiveTable("$dataurl", "${divid}", $callback ,{"maxPages":$maxPages, "limit":$count});
+    $jsName = new XWiki.widgets.LiveTable("$dataurl", "${divid}", $callback ,{"maxPages":$maxPages, "limit":$count
+      #foreach($field in $distinct)
+        #if($velocityCount == 1) , "distinct" : [ #end "$field" #if($velocityCount < $distinct.size()) , #else ] #end
+      #end
+    });
   #else
-    $jsName = new XWiki.widgets.LiveTable("$dataurl", "${divid}", #livetablecallback($divid $collist $colprops $transprefix) ,{"maxPages":$maxPages, "limit":$count});
+    $jsName = new XWiki.widgets.LiveTable("$dataurl", "${divid}", #livetablecallback($divid $collist $colprops $transprefix) ,{"maxPages":$maxPages, "limit":$count
+    #foreach($field in $distinct)
+      #if($velocityCount == 1) , "distinct" : [ #end "$field" #if($velocityCount < $distinct.size()) , #else ] #end
+    #end
+  });
   #end
    //]]>
   </script>