public static Expression dateDiffMillis(String expression1, String expression2, DatePart part) {
        return dateDiffMillis(x(expression1), x(expression2), part);
    }
public static Expression dateDiffMillis ( String expression1 , String expression2 , DatePart part ) { return dateDiffMillis ( x ( expression1 ) , x ( expression2 ) , part ) ; }
Returned expression results in Date arithmetic.
Returns the elapsed time between two UNIX timestamps as an integer whose unit is part.