Response time column

Hello, I'm checking if SC can make any calculations in custom report, we are looking to get Response time value as CreateTime - Responded Time, looks like the only option to achieve this is Custom query, but I have to idea how to make this since even copying existing report quety (it works from Report secition) causes query window fail.

Query:

SELECT std.STATUSNAME "Request Status",wo.WORKORDERID "Request ID",aau.FIRST_NAME "Contact",org.NAME "Account",wo.TITLE "Subject",wo.CREATEDTIME "Created Time",cd.CATEGORYNAME "Category",wo.RESPONDEDTIME "Responded Time",pd.PRIORITYNAME "Priority",wo.COMPLETEDTIME "Completed Time",prod.COMPONENTNAME "Product" FROM WorkOrder wo LEFT JOIN WorkOrder_Product wo_prod ON wo.WORKORDERID=wo_prod.WORKORDERID LEFT JOIN ComponentDefinition prod ON wo_prod.PRODUCT_ID=prod.COMPONENTID LEFT JOIN SDUser sdu ON wo.REQUESTERID=sdu.USERID LEFT JOIN AaaUser aau ON sdu.USERID=aau.USER_ID LEFT JOIN WorkOrderStates wos ON wo.WORKORDERID=wos.WORKORDERID LEFT JOIN CategoryDefinition cd ON wos.CATEGORYID=cd.CATEGORYID LEFT JOIN PriorityDefinition pd ON wos.PRIORITYID=pd.PRIORITYID LEFT JOIN StatusDefinition std ON wos.STATUSID=std.STATUSID LEFT JOIN WorkOrder_Account woacc ON wo.WORKORDERID=woacc.WORKORDERID LEFT JOIN Customer cust ON woacc.ACCOUNTID=cust.CUSTOMER_ID LEFT JOIN AaaOrganization org ON cust.CUSTOMER_ID=org.ORG_ID WHERE (((org.NAME = N'Test Services' COLLATE SQL_Latin1_General_CP1_CI_AS) AND (((wo.LASTUPDATED >= datetolong('2012-11-01') AND ((wo.LASTUPDATED != 0) AND (wo.LASTUPDATED IS NOT NULL))) AND ((wo.LASTUPDATED <= 1354337999000) AND (((wo.LASTUPDATED != 0) AND (wo.LASTUPDATED IS NOT NULL)) AND (wo.LASTUPDATED != -1))))) AND (wo.DEPARTMENTID = 1)) AND wo.ISPARENT=1 ORDER BY 1

Log:

java.lang.NullPointerException

at com.adventnet.servicedesk.reports.utils.CoreReportDesigner.generateSQLReport(CoreReportDesigner.java:7923)

at com.adventnet.servicedesk.reports.action.ReportRequestHandler.runSQLQueryReport(ReportRequestHandler.java:1553)

at com.adventnet.servicedesk.reports.action.ReportRequestHandler.handleRequest(ReportRequestHandler.java:1844)

at com.adventnet.servicedesk.reports.action.CustomReportHandler.handleRequest(CustomReportHandler.java:145)

at com.adventnet.servicedesk.reports.action.ReportHandler.execute(ReportHandler.java:59)

at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)

at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)

at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)

at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:237)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at com.adventnet.servicedesk.filter.EncodingFilter.doFilter(EncodingFilter.java:66)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at com.manageengine.supportcenter.service.NTLMV2CredentialAssociationFilter.doFilter(NTLMV2CredentialAssociationFilter.java:31)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at com.manageengine.supportcenter.service.NTLMV2Filter.doFilter(NTLMV2Filter.java:149)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at com.adventnet.authentication.ContextChangeDetector.doFilter(ContextChangeDetector.java:112)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:75)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:186)

at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:157)

at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:214)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)

at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)

at org.apache.catalina.core.StandardContextValve.invokeInternal(StandardContextValve.java:198)

at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:152)

at org.apache.catalina.core.StandardValveContext.invokeNext(StandardValveContext.java:104)

at org.jboss.web.tomcat.security.CustomPrincipalValve.invoke(CustomPrincipalValve.java:66)