public NumberExpression<Integer> month() {
        if (month == null) {
            month = Expressions.numberOperation(Integer.class, Ops.DateTimeOps.MONTH, mixin);
        }
        return month;
    }
Create a month expression (range 1-12 / JAN-DEC)

@return month
querydsl-core/src/main/java/com/querydsl/core/types/dsl/DateExpression.java