Пример #1
0
func (af *avgFunction) calculateResult(ctx *ast.AggEvaluateContext) (d types.Datum) {
	switch ctx.Value.Kind() {
	case types.KindFloat64:
		t := ctx.Value.GetFloat64() / float64(ctx.Count)
		d.SetValue(t)
	case types.KindMysqlDecimal:
		x := ctx.Value.GetMysqlDecimal()
		y := mysql.NewDecFromInt(ctx.Count)
		to := new(mysql.MyDecimal)
		mysql.DecimalDiv(x, y, to, mysql.DivFracIncr)
		to.Round(to, ctx.Value.Frac()+mysql.DivFracIncr)
		d.SetMysqlDecimal(to)
	}
	return
}
Пример #2
0
func (e *Evaluator) evalAggAvg(v *ast.AggregateFuncExpr) {
	ctx := v.GetContext()
	switch ctx.Value.Kind() {
	case types.KindFloat64:
		t := ctx.Value.GetFloat64() / float64(ctx.Count)
		v.SetValue(t)
	case types.KindMysqlDecimal:
		x := ctx.Value.GetMysqlDecimal()
		var y, to mysql.MyDecimal
		y.FromUint(uint64(ctx.Count))
		mysql.DecimalDiv(x, &y, &to, mysql.DivFracIncr)
		to.Round(&to, ctx.Value.Frac()+mysql.DivFracIncr)
		v.SetMysqlDecimal(&to)
	}
	ctx.Value = *v.GetDatum()
}
Пример #3
0
// GetGroupResult implements AggregationFunction interface.
func (af *avgFunction) GetGroupResult(groupKey []byte) (d types.Datum) {
	ctx := af.getContext(groupKey)
	switch ctx.Value.Kind() {
	case types.KindFloat64:
		t := ctx.Value.GetFloat64() / float64(ctx.Count)
		d.SetValue(t)
	case types.KindMysqlDecimal:
		x := ctx.Value.GetMysqlDecimal()
		y := mysql.NewDecFromInt(ctx.Count)
		to := new(mysql.MyDecimal)
		mysql.DecimalDiv(x, y, to, mysql.DivFracIncr)
		to.Round(to, ctx.Value.Frac()+mysql.DivFracIncr)
		d.SetMysqlDecimal(to)
	}
	return
}
Пример #4
0
// ComputeDiv computes the result of a/b.
func ComputeDiv(a, b Datum) (d Datum, err error) {
	// MySQL support integer division Div and division operator /
	// we use opcode.Div for division operator and will use another for integer division later.
	// for division operator, we will use float64 for calculation.
	switch a.Kind() {
	case KindFloat64:
		y, err1 := b.ToFloat64()
		if err1 != nil {
			return d, errors.Trace(err1)
		}

		if y == 0 {
			return d, nil
		}

		x := a.GetFloat64()
		d.SetFloat64(x / y)
		return d, nil
	default:
		// the scale of the result is the scale of the first operand plus
		// the value of the div_precision_increment system variable (which is 4 by default)
		// we will use 4 here
		xa, err1 := a.ToDecimal()
		if err != nil {
			return d, errors.Trace(err1)
		}

		xb, err1 := b.ToDecimal()
		if err1 != nil {
			return d, errors.Trace(err1)
		}
		// division by zero return null
		to := new(mysql.MyDecimal)
		err = mysql.DecimalDiv(xa, xb, to, mysql.DivFracIncr)
		if err != mysql.ErrDivByZero {
			d.SetMysqlDecimal(to)
		} else {
			err = nil
		}
		return d, err
	}
}
Пример #5
0
// ComputeIntDiv computes the result of a / b, both a and b are integer.
func ComputeIntDiv(a, b Datum) (d Datum, err error) {
	switch a.Kind() {
	case KindInt64:
		x := a.GetInt64()
		switch b.Kind() {
		case KindInt64:
			y := b.GetInt64()
			if y == 0 {
				return d, nil
			}
			r, err1 := DivInt64(x, y)
			d.SetInt64(r)
			return d, errors.Trace(err1)
		case KindUint64:
			y := b.GetUint64()
			if y == 0 {
				return d, nil
			}
			r, err1 := DivIntWithUint(x, y)
			d.SetUint64(r)
			return d, errors.Trace(err1)
		}
	case KindUint64:
		x := a.GetUint64()
		switch b.Kind() {
		case KindInt64:
			y := b.GetInt64()
			if y == 0 {
				return d, nil
			}
			r, err1 := DivUintWithInt(x, y)
			d.SetUint64(r)
			return d, errors.Trace(err1)
		case KindUint64:
			y := b.GetUint64()
			if y == 0 {
				return d, nil
			}
			d.SetUint64(x / y)
			return d, nil
		}
	}

	// If either is not integer, use decimal to calculate
	x, err := a.ToDecimal()
	if err != nil {
		return d, errors.Trace(err)
	}

	y, err := b.ToDecimal()
	if err != nil {
		return d, errors.Trace(err)
	}
	to := new(mysql.MyDecimal)
	err = mysql.DecimalDiv(x, y, to, mysql.DivFracIncr)
	if err == mysql.ErrDivByZero {
		return d, nil
	}
	iVal, err1 := to.ToInt()
	if err == nil {
		err = err1
	}
	d.SetInt64(iVal)
	return d, nil
}