Code
<?xml version="1.0" encoding="utf-8"?>
<mx:Application
    xmlns:mx="http://www.adobe.com/2006/mxml" 
    xmlns:esri="http://www.esri.com/2008/ags"
    pageTitle="Query Task"
    >    
    <mx:Script>
        <![CDATA[
            import com.esri.ags.Graphic;
            import com.esri.ags.tasks.FeatureSet;
            import com.esri.ags.tasks.Query;
            import mx.controls.Alert;
            import mx.rpc.AsyncResponder;
                        
            private function doQuery() : void
            {
                queryTask.execute( query, new AsyncResponder( onResult, 
onFault ));
                function onResult( featureSet : FeatureSet, token : 
Object = null ) : void
                {   
                    var displayFieldName : String = 
featureSet.displayFieldName;
                    for each ( var myGraphic : Graphic in 
featureSet.features )
                    {
                        // ToolTip
                        myGraphic.toolTip = "The 2007 population of " 
                            + myGraphic.attributes[displayFieldName] + 
" was " 
                            + myNumberFormatter.format
(myGraphic.attributes.POP2007)
                            + "\nMedian Age: " + 
myGraphic.attributes.MED_AGE + ".";       
                        // show on map
                        myGraphicsLayer.add( myGraphic ); 
                    }
                }
                function onFault( info : Object, token : Object = null 
) : void
                {
                    Alert.show( info.toString() );
                }                         
            }
        ]]>
    </mx:Script>
    <mx:NumberFormatter id="myNumberFormatter" 
useThousandsSeparator="true"/>
    <!-- Layer with US States -->
    <esri:QueryTask id="queryTask" 
url="http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demogra
phics/ESRI_Census_USA/MapServer/5">
        <esri:Query id="query" 
            text="{qText.text}"
            returnGeometry="true"
            spatialRelationship="esriSpatialRelEnvelopeIntersects">
            <esri:outFields>
                <mx:String>MED_AGE</mx:String>
                <mx:String>POP2007</mx:String>
            </esri:outFields>
        </esri:Query>
    </esri:QueryTask>
    <mx:Panel title="Query a layer (search for a state)" 
layout="horizontal" backgroundColor="0xB2BFC6" borderStyle="solid">
        <mx:TextInput width="100%" id="qText" enter="doQuery()" 
text="California"/>
        <mx:Button label="Do Query" click="doQuery()"/>            
    </mx:Panel>
    <esri:Map>
        <esri:extent>
            <esri:Extent xmin="-170" ymin="15" xmax="-65" ymax="75"/>
        </esri:extent>
        <esri:ArcGISTiledMapServiceLayer
            
url="http://server.arcgisonline.com/ArcGIS/rest/services/NPS_Physical_W
orld_2D/MapServer" />
        <esri:GraphicsLayer id="myGraphicsLayer"/>
    </esri:Map>
</mx:Application>