JPQL and date comparison (constraint in the query)

My Application model object contains a date field (time stamp):

@Entity
@Table(name = "M开发者_开发百科YTABLE")
public class Application {

   private Date timeStamp;
   ...
}

I'm trying to construct a JPQL query that would select all applications that were changed today (i.e. their time stamp was changed anytime today). What is the best way to do this?

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There is no perfect way with standard JPQL, JPQL doesn't provide Date arithmetic functions. But your provider might provide extensions (e.g. Hibernate and EclipseLink do). Or use a native SQL.