public static <T> WindowOver<T> nthValue(Expression<T> expr, Expression<? extends Number> n) {
        return new WindowOver<T>(expr.getType(), SQLOps.NTHVALUE, expr, n);
    }
NTH_VALUE returns the expr value of the nth row in the window defined by the analytic clause.
The returned value has the data type of the expr

@param expr measure expression
@param n one based row index
@return nth_value(expr, n)
querydsl-sql/src/main/java/com/querydsl/sql/SQLExpressions.java