if err != nil {
		return nil, err
	}
	if err = inferTypeAsTimestamp(tval1); err != nil {
		return nil, err
	}
	ts1, ok := tval1.ToTimestamp()
	if !ok {
		return nil, fmt.Errorf("%s() expects two timestamp arguments", sqlFnDateDiff)
	}

	tval2, err := d.Timestamp2.evalNode(r, tableAlias)
	if err != nil {
		return nil, err
	}
	if err = inferTypeAsTimestamp(tval2); err != nil {
		return nil, err
	}

	floatA, _ := a.ToFloat()
	var result float64
	if !isMax {
		result = math.Min(floatV, floatA)
	} else {
		result = math.Max(floatV, floatA)
	}
	v.setFloat(result)
	return nil
}

func inferTypeAsTimestamp(v *Value) error {
	if s, ok := v.ToString(); ok {
		t, err := parseSQLTimestamp(s)
		if err != nil {
			return err
		}
		v.setTimestamp(t)
	} else if b, ok := v.ToBytes(); ok {
		s := string(b)