Amateur in AIF Webservices

Hi,

I am an amateur to Axapta. I am in a WCF integration project with AIF Webservices. How can I build a Query Criteria with multiple fields and queries. for eg: SQL QUERY LIKE:

(SELECT itemId,itemgroupid,itemname,dataareaid FROM INVENTTABLE WHERE dataareaid='12AC' and itemgroupid ='CEMENT01';)

How should I build the above query to fetch the above fields. Also how should I return the results as array in the same method WCF service.

ItemService.AxdItem axdItem = newAxdItem();

AxdEntity_InventTable objinventTable;

var inventItemColl = new ItemService.QueryCriteria();

var inventElement = newList<ItemService.CriteriaElement>();

//OR 

inventElement.Add(new ItemService.CriteriaElement {

DataSourceName = "InventTable",

FieldName = "itemId",

Operator= ItemService.Operator.Range,

Value1="CON002"

,Value2="CON008"});

inventElement.Add(new ItemService.CriteriaElement

{

DataSourceName = "InventTable",

FieldName = "itemId,itemname,dataareaid",

Operator = ItemService.Operator.Equal,

Value1 ="*",Value2=""

});

inventItemColl.CriteriaElement = inventElement.ToArray();