@ConstantFunction(name = "quarters_sub", argTypes = {DATETIME, INT}, returnType = DATETIME, isMonotonic = true)
    public static ConstantOperator quartersSub(ConstantOperator date, ConstantOperator quarter) {
        return ConstantOperator.createDatetimeOrNull(
                date.getDatetime().minus(quarter.getInt(), IsoFields.QUARTER_YEARS));
    }
@Test
    public void quartersSub() {
        assertEquals("2014-12-23T09:23:55",
                ScalarOperatorFunctions.quartersSub(O_DT_20150323_092355, O_INT_1).getDatetime().toString());
    }