func (a *decimalVarianceAggregate) result() (parser.Datum, error) {
if a.count.Cmp(decimalTwo) < 0 {
return parser.DNull, nil
}
a.tmp.Sub(&a.count, decimalOne)
dd := parser.DDecimal{}
dd.QuoRound(&a.sqrDiff, &a.tmp, decimal.Precision, inf.RoundHalfUp)
return dd, nil
}
