public WindowFunction<A> orderBy(ComparableExpressionBase<?>... orderBy) {
        value = null;
        for (ComparableExpressionBase<?> e : orderBy) {
            this.orderBy.add(e.asc());
        }
        return this;
    }
{@code WindowFunction} is a builder for window function expressions

@param <A> expression type

@author tiwe
querydsl-sql/src/main/java/com/querydsl/sql/WindowFunction.java