public static <T> WindowOver<T> ratioToReport(Expression<T> expr) {
        return new WindowOver<T>(expr.getType(), SQLOps.RATIOTOREPORT, expr);
    }
computes the ratio of a value to the sum of a set of values. If expr evaluates to null,
then the ratio-to-report value also evaluates to null.

@return ratio_to_report(expr)
querydsl-sql/src/main/java/com/querydsl/sql/SQLExpressions.java