Sol:

Create custom function Alias

Step 1: Just copy by saving as the OOTB DifferenceinMinutes function alias.

Step 2: replace with below

<p:choose> <p:when test=".pyParameters(1).pyUserEnteredDataType == 'DATETIME' && .pyParameters(2).pyUserEnteredDataType =='DATETIME'">      <p:choose>                  <p:when test=".pyParameters(1).pyDBDataType =='TIMESTAMP'  && .pyParameters(2).pyDBDataType =='TIMESTAMP' ">              ROUND(( CAST({2} AS DATE) - CAST({1} AS DATE) )*86400)         </p:when>                </p:choose>    </p:when>

<p:otherwise>     ERROR : INCOMPATIBLE TYPES ENTERED </p:otherwise>

</p:choose>

3) Apply in Report definition

4) In RD row apply custom HTML property (Control)to the property that needs the date in this format  days,hrs,mins,secs. ( aka Control that displays as  2days, 3 hrs, 2mins, 6 secs format). For this create below custom control

       1) Saves OOTB "DateDifference" control  to your custom name say for ex "DateDifferenceInSeconds"

       2) Then eplace with below code :

<% double totalSecs=0; totalSecs = Double.parseDouble(tools.getActive().getStringValue());

String display;

if(totalSecs>0){     double dDays   = Math.floor(totalSecs / 3600); // get hours     double dHours   = Math.floor(totalSecs / 3600); // get hours     double dMins = Math.floor((totalSecs - (dHours * 3600)) / 60); // get minutes     double dSecs = totalSecs - (dHours * 3600) - (dMins * 60); //  get seconds     

display = Integer.toString((int)dDays) + " Days, " + Integer.toString((int)dHours) + " Hours, " + Integer.toString((int)dMins) + "Mins, " +Integer.toString((int)dSecs) + "Secs" ;

} else {

display ="0 Days, " + " 0 Hours, " + "0 Mins, "+"0 Secs"; }

%> <div><%=display%></div>