Exemplo n.º 1
0
func computeDiv(a, b types.Datum) (d types.Datum, err error) {
	// MySQL support integer divison 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 types.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)
		}
		if f, _ := xb.Float64(); f == 0 {
			// division by zero return null
			return d, nil
		}

		d.SetMysqlDecimal(xa.Div(xb))
		return d, nil
	}
}
Exemplo n.º 2
0
func computeIntDiv(a, b types.Datum) (d types.Datum, err error) {
	switch a.Kind() {
	case types.KindInt64:
		x := a.GetInt64()
		switch b.Kind() {
		case types.KindInt64:
			y := b.GetInt64()
			if y == 0 {
				return d, nil
			}
			r, err1 := types.DivInt64(x, y)
			d.SetInt64(r)
			return d, errors.Trace(err1)
		case types.KindUint64:
			y := b.GetUint64()
			if y == 0 {
				return d, nil
			}
			r, err1 := types.DivIntWithUint(x, y)
			d.SetUint64(r)
			return d, errors.Trace(err1)
		}
	case types.KindUint64:
		x := a.GetUint64()
		switch b.Kind() {
		case types.KindInt64:
			y := b.GetInt64()
			if y == 0 {
				return d, nil
			}
			r, err1 := types.DivUintWithInt(x, y)
			d.SetUint64(r)
			return d, errors.Trace(err1)
		case types.KindUint64:
			y := b.GetUint64()
			if y == 0 {
				return d, nil
			}
			d.SetUint64(x / y)
			return d, nil
		}
	}

	// if any is none 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)
	}

	if f, _ := y.Float64(); f == 0 {
		return d, nil
	}

	d.SetInt64(x.Div(y).IntPart())
	return d, nil
}