func builtinAvg(args []interface{}, ctx map[interface{}]interface{}) (v interface{}, err error) {
// avg use decimal for integer and decimal type, use float for others
// see https://dev.mysql.com/doc/refman/5.7/en/group-by-functions.html
type avg struct {
sum interface{}
n uint64
decimalResult bool
}
if _, ok := ctx[ExprEvalArgAggEmpty]; ok {
return
}
fn := ctx[ExprEvalFn]
distinct := getDistinct(ctx, fn)
if _, ok := ctx[ExprAggDone]; ok {
distinct.clear()
data, ok := ctx[fn].(avg)
if !ok {
return
}
switch x := data.sum.(type) {
case float64:
return float64(x) / float64(data.n), nil
case mysql.Decimal:
return x.Div(mysql.NewDecimalFromUint(data.n, 0)), nil
}
panic("should not happend")
}
data, _ := ctx[fn].(avg)
y := args[0]
if y == nil {
return
}
ok, err := distinct.isDistinct(args...)
if err != nil || !ok {
// if err or not distinct, return
return nil, err
}
if data.sum == nil {
data.n = 0
}
data.sum, err = calculateSum(data.sum, y)
if err != nil {
return nil, errors.Errorf("eval AVG aggregate err: %v", err)
}
data.n++
ctx[fn] = data
return
}
func (s *testTypeEtcSuite) TestCoerce(c *C) {
checkCoerce(c, uint64(3), int16(4))
checkCoerce(c, uint64(0xffffffffffffffff), float64(2.3))
checkCoerce(c, float64(1.3), uint64(0xffffffffffffffff))
checkCoerce(c, int64(11), float64(4.313))
checkCoerce(c, uint(2), uint16(52))
checkCoerce(c, uint8(8), true)
checkCoerce(c, uint32(62), int8(8))
checkCoerce(c, mysql.NewDecimalFromInt(1, 0), false)
checkCoerce(c, float32(3.4), mysql.NewDecimalFromUint(1, 0))
checkCoerce(c, int32(43), 3.235)
}
// CastValue casts a value based on column's type.
func (c *Col) CastValue(ctx context.Context, val interface{}) (casted interface{}, err error) {
if val == nil {
return
}
switch c.Tp {
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong, mysql.TypeYear, mysql.TypeBit:
intVal, errCode := c.normalizeIntegerValue(val)
if errCode == errCodeType {
casted = intVal
err = c.TypeError(val)
return
}
return c.castIntegerValue(intVal, errCode)
case mysql.TypeFloat, mysql.TypeDouble:
return c.castFloatValue(val)
case mysql.TypeDate, mysql.TypeDatetime, mysql.TypeTimestamp:
switch v := val.(type) {
case int64:
casted, err = mysql.ParseTimeFromNum(v, c.Tp, c.Decimal)
if err != nil {
err = newParseColError(err, c)
}
case string:
casted, err = mysql.ParseTime(v, c.Tp, c.Decimal)
if err != nil {
err = newParseColError(err, c)
}
case mysql.Time:
var t mysql.Time
t, err = v.Convert(c.Tp)
if err != nil {
err = newParseColError(err, c)
return
}
casted, err = t.RoundFrac(c.Decimal)
if err != nil {
err = newParseColError(err, c)
}
default:
err = c.TypeError(val)
}
case mysql.TypeDuration:
switch v := val.(type) {
case string:
casted, err = mysql.ParseDuration(v, c.Decimal)
if err != nil {
err = newParseColError(err, c)
}
case mysql.Time:
var t mysql.Duration
t, err = v.ConvertToDuration()
if err != nil {
err = newParseColError(err, c)
return
}
casted, err = t.RoundFrac(c.Decimal)
if err != nil {
err = newParseColError(err, c)
}
case mysql.Duration:
casted, err = v.RoundFrac(c.Decimal)
default:
err = c.TypeError(val)
}
case mysql.TypeBlob, mysql.TypeTinyBlob, mysql.TypeMediumBlob, mysql.TypeLongBlob, mysql.TypeString, mysql.TypeVarchar, mysql.TypeVarString:
strV := ""
switch v := val.(type) {
case mysql.Time:
strV = v.String()
case mysql.Duration:
strV = v.String()
case []byte:
if c.Charset == charset.CharsetBin {
casted = v
return
}
strV = string(v)
default:
strV = fmt.Sprintf("%v", val)
}
if (c.Flen != types.UnspecifiedLength) && (len(strV) > c.Flen) {
strV = strV[:c.Flen]
}
casted = strV
case mysql.TypeDecimal, mysql.TypeNewDecimal:
switch v := val.(type) {
case string:
casted, err = mysql.ParseDecimal(v)
if err != nil {
err = newParseColError(err, c)
}
case int8:
casted = mysql.NewDecimalFromInt(int64(v), 0)
case int16:
casted = mysql.NewDecimalFromInt(int64(v), 0)
case int32:
casted = mysql.NewDecimalFromInt(int64(v), 0)
case int64:
casted = mysql.NewDecimalFromInt(int64(v), 0)
case int:
casted = mysql.NewDecimalFromInt(int64(v), 0)
case uint8:
casted = mysql.NewDecimalFromUint(uint64(v), 0)
case uint16:
casted = mysql.NewDecimalFromUint(uint64(v), 0)
case uint32:
casted = mysql.NewDecimalFromUint(uint64(v), 0)
case uint64:
casted = mysql.NewDecimalFromUint(uint64(v), 0)
case uint:
casted = mysql.NewDecimalFromUint(uint64(v), 0)
case float32:
casted = mysql.NewDecimalFromFloat(float64(v))
case float64:
casted = mysql.NewDecimalFromFloat(float64(v))
case mysql.Decimal:
casted = v
}
default:
err = c.TypeError(val)
}
return
}