Quantity  *Operand     `parser:" @@ \",\""`
	Timestamp *PrimaryTerm `parser:" @@ \")\""`
}

// DateDiffFunc represents the DATE_DIFF function
type DateDiffFunc struct {

	case timePartYear:
		dy := int64(y2 - y1)
		if m2 > m1 || (m2 == m1 && d2 >= d1) {
			return FromInt(dy), nil
		}
		return FromInt(dy - 1), nil
	case timePartMonth:
		m1 += time.Month(12 * y1)
		m2 += time.Month(12 * y2)

		return FromInt(int64(m2 - m1)), nil
	case timePartDay:
		return FromInt(int64(duration / (24 * time.Hour))), nil
	case timePartHour:
		hours := duration / time.Hour

	}

	months, err := strconv.Atoi(strings.TrimSuffix(s, "m"))
	if err != nil {
		return -1, err
	}

	if months < minimumBitrotCycleInMonths {
		return -1, fmt.Errorf("minimum bitrot cycle is %d month(s)", minimumBitrotCycleInMonths)
	}

	return time.Duration(months) * 30 * 24 * time.Hour, nil
}

// LookupConfig - lookup config and override with valid environment settings if any.

		{15 * 24 * time.Hour, "my_download_url", "2 weeks before the latest release"},

		// Testcase index 20
		{30 * 24 * time.Hour, "my_download_url", "1 month before the latest release"},
		{31 * 24 * time.Hour, "my_download_url", "1 month before the latest release"},
		{61 * 24 * time.Hour, "my_download_url", "2 months before the latest release"},
		{360 * 24 * time.Hour, "my_download_url", "1 year before the latest release"},

		"sum(2 + s.id)",
		"sum(t)",
		"avg(s.id[1])",
		"coalesce(s.id[1], 2, 2 + 3)",

		"cast(s as string)",
		"cast(s AS INT)",
		"cast(s as DECIMAL)",
		"extract(YEAR from '2018-01-09')",
		"extract(month from '2018-01-09')",

		"extract(hour from '2018-01-09')",
		"extract(day from '2018-01-09')",
		"substring('abcd' from 2 for 2)",
		"substring('abcd' from 2)",
		"substring('abcd' , 2 , 2)",

			query:      `SELECT date_diff(month, '2010-01-01T', '2010-05T') FROM S3Object LIMIT 1`,
			wantResult: `{"_1":4}`,
		},
		{
			name:       "date_diff_month_oney",
			query:      `SELECT date_diff(month, '2010T', '2011T') FROM S3Object LIMIT 1`,
			wantResult: `{"_1":12}`,
		},
		{
			name:       "date_diff_month_neg",
			query:      `SELECT date_diff(month, '2011T', '2010T') FROM S3Object LIMIT 1`,