func (e *Evaluator) evalAggAvg(v *ast.AggregateFuncExpr) {
ctx := v.GetContext()
switch x := ctx.Value.(type) {
case float64:
t := x / float64(ctx.Count)
ctx.Value = t
v.SetFloat64(t)
case mysql.Decimal:
t := x.Div(mysql.NewDecimalFromUint(uint64(ctx.Count), 0))
ctx.Value = t
v.SetMysqlDecimal(t)
}
}
