[news.eclipse.rt.eclipselink] Expression - dateDifference method usage

[kenneth.unpingco@xxxxxxxxxx (Kenneth Unpingco)]

Hello, 

I am trying to use the class: 
org.eclipse.persistence.expressions.Expression by invoking the 
dateDifference method:

public Expression dateDifference(java.lang.String datePart,           
Expression comparisonExpression).

However, when I tried to use it I got the following error 
exception:SybSQLException: 'MOD_DATE' is not a recognized datediff option.
All that I am trying to do is to get the total seconds elapsed between two 
datetime columns (in my case, its the modDate column) from a table called 
DocStore.  I've made sure from the JavaDoc API that I've put in the 
correct parameters. 

I've used the following statement:
responseRequestDateTimeDifferenceExpression =  
		   
addrProcessExpression.get("requestDoc").get("modDate").dateDifference("second", 
addrProcessExpression.get("responseDoc").get("modDate"));

I expected the SQL transformation to get something like:
DATEDIFF(second, responseDoc.MOD_DATE, requestDoc.MOD_DATE) 
but that did not happen. I ran across the datediff error exception. Shown 
below are further details of the code and error exception.  

What am I doing wrong? Any advice or ideas are truly appreciated. 

Thank you,
Ken Unpingco  
**************************
Here is the java code:
addrProcessExpression = new ExpressionBuilder();
reportQuery = new ReportQuery(AddressProcess.class, addrProcessExpression);
requestResponseDateRangeExpression =    
		   
addrProcessExpression.get("requestDoc").get("modDate").between(startDate, 
endDate)
		      
and(addrProcessExpression.get("responseDoc").get("modDate").between(startDate, 
endDate))
		      .and(addrProcessExpression.get("responseDoc").notEqual(null))
		      .and(addrProcessExpression.get("requestDoc").notEqual(null));	
		
responseRequestDateTimeDifferenceExpression =  
		   
addrProcessExpression.get("requestDoc").get("modDate").dateDifference("second", 
addrProcessExpression.get("responseDoc").get("modDate"));
				
reportQuery.setShouldReturnSingleValue(true);
		
reportQuery.addSum("Total-seconds", 
responseRequestDateTimeDifferenceExpression);
		
reportQuery.setSelectionCriteria(requestResponseDateRangeExpression);
Query query = JpaHelper.createQuery(reportQuery, 
(EntityManager)em.getDelegate());
   
******** Details for the log on the exception 
******************************** 
Exception [EclipseLink-4002] (Eclipse Persistence Services - 
2.0.0.v20090424-r4050): 
org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.sybase.jdbc3.jdbc.SybSQLException: 'MOD_DATE' is 
not a recognized datediff option.

Error Code: 155
Call: SELECT SUM(DATEDIFF(t0.MOD_DATE, t3.MOD_DATE, t0.MOD_DATE)) FROM 
DOCSTORE t3, ADDRESS_PROCESS t2, PROCESS t1, DOCSTORE t0 WHERE 
((((((t0.MOD_DATE BETWEEN ? AND ?) AND (t3.MOD_DATE BETWEEN ? AND ?)) AND 
NOT ((t2.RESPONSE_DOC_ID IS NULL))) AND NOT ((t2.REQUEST_DOC_ID IS NULL))) 
AND ((t2.ID = t1.ID) AND (t1.discriminator = ?))) AND ((t0.ID = 
t2.REQUEST_DOC_ID) AND (t3.ID = t2.RESPONSE_DOC_ID)))
	bind => [2009-01-01 00:00:00.0, 2009-05-09 00:00:00.0, 2009-01-01 
00:00:00.0, 2009-05-09 00:00:00.0, Address]
Query: ReportQuery(referenceClass=AddressProcess sql="SELECT 
SUM(DATEDIFF(t0.MOD_DATE, t3.MOD_DATE, t0.MOD_DATE)) FROM DOCSTORE t3, 
ADDRESS_PROCESS t2, PROCESS t1, DOCSTORE t0 WHERE ((((((t0.MOD_DATE 
BETWEEN ? AND ?) AND (t3.MOD_DATE BETWEEN ? AND ?)) AND NOT 
((t2.RESPONSE_DOC_ID IS NULL))) AND NOT ((t2.REQUEST_DOC_ID IS NULL))) AND 
((t2.ID = t1.ID) AND (t1.discriminator = ?))) AND ((t0.ID = 
t2.REQUEST_DOC_ID) AND (t3.ID = t2.RESPONSE_DOC_ID)))")
root cause 

com.sybase.jdbc3.jdbc.SybSQLException: 'MOD_DATE' is not a recognized 
datediff option.