You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
418 lines
16 KiB
418 lines
16 KiB
// Copyright 2018 PingCAP, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package aggregation
|
|
|
|
import (
|
|
"bytes"
|
|
"fmt"
|
|
"math"
|
|
"strings"
|
|
|
|
"github.com/cznic/mathutil"
|
|
"github.com/pingcap/errors"
|
|
"github.com/pingcap/parser/ast"
|
|
"github.com/pingcap/parser/charset"
|
|
"github.com/pingcap/parser/mysql"
|
|
"github.com/pingcap/tidb/expression"
|
|
"github.com/pingcap/tidb/sessionctx"
|
|
"github.com/pingcap/tidb/types"
|
|
"github.com/pingcap/tidb/util/chunk"
|
|
)
|
|
|
|
// baseFuncDesc describes an function signature, only used in planner.
|
|
type baseFuncDesc struct {
|
|
// Name represents the function name.
|
|
Name string
|
|
// Args represents the arguments of the function.
|
|
Args []expression.Expression
|
|
// RetTp represents the return type of the function.
|
|
RetTp *types.FieldType
|
|
}
|
|
|
|
func newBaseFuncDesc(ctx sessionctx.Context, name string, args []expression.Expression) (baseFuncDesc, error) {
|
|
b := baseFuncDesc{Name: strings.ToLower(name), Args: args}
|
|
err := b.typeInfer(ctx)
|
|
return b, err
|
|
}
|
|
|
|
func (a *baseFuncDesc) equal(ctx sessionctx.Context, other *baseFuncDesc) bool {
|
|
if a.Name != other.Name || len(a.Args) != len(other.Args) {
|
|
return false
|
|
}
|
|
for i := range a.Args {
|
|
if !a.Args[i].Equal(ctx, other.Args[i]) {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (a *baseFuncDesc) clone() *baseFuncDesc {
|
|
clone := *a
|
|
newTp := *a.RetTp
|
|
clone.RetTp = &newTp
|
|
clone.Args = make([]expression.Expression, len(a.Args))
|
|
for i := range a.Args {
|
|
clone.Args[i] = a.Args[i].Clone()
|
|
}
|
|
return &clone
|
|
}
|
|
|
|
// String implements the fmt.Stringer interface.
|
|
func (a *baseFuncDesc) String() string {
|
|
buffer := bytes.NewBufferString(a.Name)
|
|
buffer.WriteString("(")
|
|
for i, arg := range a.Args {
|
|
buffer.WriteString(arg.String())
|
|
if i+1 != len(a.Args) {
|
|
buffer.WriteString(", ")
|
|
}
|
|
}
|
|
buffer.WriteString(")")
|
|
return buffer.String()
|
|
}
|
|
|
|
// typeInfer infers the arguments and return types of an function.
|
|
func (a *baseFuncDesc) typeInfer(ctx sessionctx.Context) error {
|
|
switch a.Name {
|
|
case ast.AggFuncCount:
|
|
a.typeInfer4Count(ctx)
|
|
case ast.AggFuncApproxCountDistinct:
|
|
a.typeInfer4ApproxCountDistinct(ctx)
|
|
case ast.AggFuncApproxPercentile:
|
|
return a.typeInfer4ApproxPercentile(ctx)
|
|
case ast.AggFuncSum:
|
|
a.typeInfer4Sum(ctx)
|
|
case ast.AggFuncAvg:
|
|
a.typeInfer4Avg(ctx)
|
|
case ast.AggFuncGroupConcat:
|
|
a.typeInfer4GroupConcat(ctx)
|
|
case ast.AggFuncMax, ast.AggFuncMin, ast.AggFuncFirstRow,
|
|
ast.WindowFuncFirstValue, ast.WindowFuncLastValue, ast.WindowFuncNthValue:
|
|
a.typeInfer4MaxMin(ctx)
|
|
case ast.AggFuncBitAnd, ast.AggFuncBitOr, ast.AggFuncBitXor:
|
|
a.typeInfer4BitFuncs(ctx)
|
|
case ast.WindowFuncRowNumber, ast.WindowFuncRank, ast.WindowFuncDenseRank:
|
|
a.typeInfer4NumberFuncs()
|
|
case ast.WindowFuncCumeDist:
|
|
a.typeInfer4CumeDist()
|
|
case ast.WindowFuncNtile:
|
|
a.typeInfer4Ntile()
|
|
case ast.WindowFuncPercentRank:
|
|
a.typeInfer4PercentRank()
|
|
case ast.WindowFuncLead, ast.WindowFuncLag:
|
|
a.typeInfer4LeadLag(ctx)
|
|
case ast.AggFuncVarPop, ast.AggFuncStddevPop, ast.AggFuncVarSamp, ast.AggFuncStddevSamp:
|
|
a.typeInfer4PopOrSamp(ctx)
|
|
case ast.AggFuncJsonObjectAgg:
|
|
a.typeInfer4JsonFuncs(ctx)
|
|
default:
|
|
return errors.Errorf("unsupported agg function: %s", a.Name)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4Count(ctx sessionctx.Context) {
|
|
a.RetTp = types.NewFieldType(mysql.TypeLonglong)
|
|
a.RetTp.Flen = 21
|
|
a.RetTp.Decimal = 0
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4ApproxCountDistinct(ctx sessionctx.Context) {
|
|
a.typeInfer4Count(ctx)
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4ApproxPercentile(ctx sessionctx.Context) error {
|
|
if len(a.Args) != 2 {
|
|
return errors.New("APPROX_PERCENTILE should take 2 arguments")
|
|
}
|
|
|
|
if !a.Args[1].ConstItem(ctx.GetSessionVars().StmtCtx) {
|
|
return errors.New("APPROX_PERCENTILE should take a constant expression as percentage argument")
|
|
}
|
|
percent, isNull, err := a.Args[1].EvalInt(ctx, chunk.Row{})
|
|
if err != nil {
|
|
return errors.New(fmt.Sprintf("APPROX_PERCENTILE: Invalid argument %s", a.Args[1].String()))
|
|
}
|
|
if percent <= 0 || percent > 100 || isNull {
|
|
if isNull {
|
|
return errors.New("APPROX_PERCENTILE: Percentage value cannot be NULL")
|
|
}
|
|
return errors.New(fmt.Sprintf("Percentage value %d is out of range [1, 100]", percent))
|
|
}
|
|
|
|
switch a.Args[0].GetType().Tp {
|
|
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong:
|
|
a.RetTp = types.NewFieldType(mysql.TypeLonglong)
|
|
case mysql.TypeDouble, mysql.TypeFloat:
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
case mysql.TypeNewDecimal:
|
|
a.RetTp = types.NewFieldType(mysql.TypeNewDecimal)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxDecimalWidth, a.Args[0].GetType().Decimal
|
|
if a.RetTp.Decimal < 0 || a.RetTp.Decimal > mysql.MaxDecimalScale {
|
|
a.RetTp.Decimal = mysql.MaxDecimalScale
|
|
}
|
|
case mysql.TypeDate, mysql.TypeDatetime, mysql.TypeNewDate, mysql.TypeTimestamp:
|
|
a.RetTp = a.Args[0].GetType().Clone()
|
|
default:
|
|
a.RetTp = a.Args[0].GetType().Clone()
|
|
a.RetTp.Flag &= ^mysql.NotNullFlag
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// typeInfer4Sum should returns a "decimal", otherwise it returns a "double".
|
|
// Because child returns integer or decimal type.
|
|
func (a *baseFuncDesc) typeInfer4Sum(ctx sessionctx.Context) {
|
|
switch a.Args[0].GetType().Tp {
|
|
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong, mysql.TypeYear:
|
|
a.RetTp = types.NewFieldType(mysql.TypeNewDecimal)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxDecimalWidth, 0
|
|
case mysql.TypeNewDecimal:
|
|
a.RetTp = types.NewFieldType(mysql.TypeNewDecimal)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxDecimalWidth, a.Args[0].GetType().Decimal
|
|
if a.RetTp.Decimal < 0 || a.RetTp.Decimal > mysql.MaxDecimalScale {
|
|
a.RetTp.Decimal = mysql.MaxDecimalScale
|
|
}
|
|
case mysql.TypeDouble, mysql.TypeFloat:
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxRealWidth, a.Args[0].GetType().Decimal
|
|
default:
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxRealWidth, types.UnspecifiedLength
|
|
}
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
}
|
|
|
|
// typeInfer4Avg should returns a "decimal", otherwise it returns a "double".
|
|
// Because child returns integer or decimal type.
|
|
func (a *baseFuncDesc) typeInfer4Avg(ctx sessionctx.Context) {
|
|
switch a.Args[0].GetType().Tp {
|
|
case mysql.TypeTiny, mysql.TypeShort, mysql.TypeInt24, mysql.TypeLong, mysql.TypeLonglong, mysql.TypeYear, mysql.TypeNewDecimal:
|
|
a.RetTp = types.NewFieldType(mysql.TypeNewDecimal)
|
|
if a.Args[0].GetType().Decimal < 0 {
|
|
a.RetTp.Decimal = mysql.MaxDecimalScale
|
|
} else {
|
|
a.RetTp.Decimal = mathutil.Min(a.Args[0].GetType().Decimal+types.DivFracIncr, mysql.MaxDecimalScale)
|
|
}
|
|
a.RetTp.Flen = mysql.MaxDecimalWidth
|
|
case mysql.TypeDouble, mysql.TypeFloat:
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxRealWidth, a.Args[0].GetType().Decimal
|
|
default:
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxRealWidth, types.UnspecifiedLength
|
|
}
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4GroupConcat(ctx sessionctx.Context) {
|
|
a.RetTp = types.NewFieldType(mysql.TypeVarString)
|
|
a.RetTp.Charset, a.RetTp.Collate = charset.GetDefaultCharsetAndCollate()
|
|
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxBlobWidth, 0
|
|
// TODO: a.Args[i] = expression.WrapWithCastAsString(ctx, a.Args[i])
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4MaxMin(ctx sessionctx.Context) {
|
|
_, argIsScalaFunc := a.Args[0].(*expression.ScalarFunction)
|
|
if argIsScalaFunc && a.Args[0].GetType().Tp == mysql.TypeFloat {
|
|
// For scalar function, the result of "float32" is set to the "float64"
|
|
// field in the "Datum". If we do not wrap a cast-as-double function on a.Args[0],
|
|
// error would happen when extracting the evaluation of a.Args[0] to a ProjectionExec.
|
|
tp := types.NewFieldType(mysql.TypeDouble)
|
|
tp.Flen, tp.Decimal = mysql.MaxRealWidth, types.UnspecifiedLength
|
|
types.SetBinChsClnFlag(tp)
|
|
a.Args[0] = expression.BuildCastFunction(ctx, a.Args[0], tp)
|
|
}
|
|
a.RetTp = a.Args[0].GetType()
|
|
if (a.Name == ast.AggFuncMax || a.Name == ast.AggFuncMin) && a.RetTp.Tp != mysql.TypeBit {
|
|
a.RetTp = a.Args[0].GetType().Clone()
|
|
a.RetTp.Flag &^= mysql.NotNullFlag
|
|
}
|
|
// issue #13027, #13961
|
|
if (a.RetTp.Tp == mysql.TypeEnum || a.RetTp.Tp == mysql.TypeSet) &&
|
|
(a.Name != ast.AggFuncFirstRow && a.Name != ast.AggFuncMax && a.Name != ast.AggFuncMin) {
|
|
a.RetTp = &types.FieldType{Tp: mysql.TypeString, Flen: mysql.MaxFieldCharLength}
|
|
}
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4BitFuncs(ctx sessionctx.Context) {
|
|
a.RetTp = types.NewFieldType(mysql.TypeLonglong)
|
|
a.RetTp.Flen = 21
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
a.RetTp.Flag |= mysql.UnsignedFlag | mysql.NotNullFlag
|
|
// TODO: a.Args[0] = expression.WrapWithCastAsInt(ctx, a.Args[0])
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4JsonFuncs(ctx sessionctx.Context) {
|
|
a.RetTp = types.NewFieldType(mysql.TypeJSON)
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4NumberFuncs() {
|
|
a.RetTp = types.NewFieldType(mysql.TypeLonglong)
|
|
a.RetTp.Flen = 21
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4CumeDist() {
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxRealWidth, mysql.NotFixedDec
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4Ntile() {
|
|
a.RetTp = types.NewFieldType(mysql.TypeLonglong)
|
|
a.RetTp.Flen = 21
|
|
types.SetBinChsClnFlag(a.RetTp)
|
|
a.RetTp.Flag |= mysql.UnsignedFlag
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4PercentRank() {
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flag, a.RetTp.Decimal = mysql.MaxRealWidth, mysql.NotFixedDec
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4LeadLag(ctx sessionctx.Context) {
|
|
if len(a.Args) <= 2 {
|
|
a.typeInfer4MaxMin(ctx)
|
|
} else {
|
|
// Merge the type of first and third argument.
|
|
a.RetTp = expression.InferType4ControlFuncs(a.Args[0].GetType(), a.Args[2].GetType())
|
|
}
|
|
}
|
|
|
|
func (a *baseFuncDesc) typeInfer4PopOrSamp(ctx sessionctx.Context) {
|
|
//var_pop/std/var_samp/stddev_samp's return value type is double
|
|
a.RetTp = types.NewFieldType(mysql.TypeDouble)
|
|
a.RetTp.Flen, a.RetTp.Decimal = mysql.MaxRealWidth, types.UnspecifiedLength
|
|
}
|
|
|
|
// GetDefaultValue gets the default value when the function's input is null.
|
|
// According to MySQL, default values of the function are listed as follows:
|
|
// e.g.
|
|
// Table t which is empty:
|
|
// +-------+---------+---------+
|
|
// | Table | Field | Type |
|
|
// +-------+---------+---------+
|
|
// | t | a | int(11) |
|
|
// +-------+---------+---------+
|
|
//
|
|
// Query: `select avg(a), sum(a), count(a), bit_xor(a), bit_or(a), bit_and(a), max(a), min(a), group_concat(a), approx_count_distinct(a), approx_percentile(a, 50) from test.t;`
|
|
// +--------+--------+----------+------------+-----------+----------------------+--------+--------+-----------------+--------------------------+--------------------------+
|
|
// | avg(a) | sum(a) | count(a) | bit_xor(a) | bit_or(a) | bit_and(a) | max(a) | min(a) | group_concat(a) | approx_count_distinct(a) | approx_percentile(a, 50) |
|
|
// +--------+--------+----------+------------+-----------+----------------------+--------+--------+-----------------+--------------------------+--------------------------+
|
|
// | NULL | NULL | 0 | 0 | 0 | 18446744073709551615 | NULL | NULL | NULL | 0 | NULL |
|
|
// +--------+--------+----------+------------+-----------+----------------------+--------+--------+-----------------+--------------------------+--------------------------+
|
|
func (a *baseFuncDesc) GetDefaultValue() (v types.Datum) {
|
|
switch a.Name {
|
|
case ast.AggFuncCount, ast.AggFuncBitOr, ast.AggFuncBitXor:
|
|
v = types.NewIntDatum(0)
|
|
case ast.AggFuncApproxCountDistinct:
|
|
if a.RetTp.Tp != mysql.TypeString {
|
|
v = types.NewIntDatum(0)
|
|
}
|
|
case ast.AggFuncFirstRow, ast.AggFuncAvg, ast.AggFuncSum, ast.AggFuncMax,
|
|
ast.AggFuncMin, ast.AggFuncGroupConcat, ast.AggFuncApproxPercentile:
|
|
v = types.Datum{}
|
|
case ast.AggFuncBitAnd:
|
|
v = types.NewUintDatum(uint64(math.MaxUint64))
|
|
}
|
|
return
|
|
}
|
|
|
|
// We do not need to wrap cast upon these functions,
|
|
// since the EvalXXX method called by the arg is determined by the corresponding arg type.
|
|
var noNeedCastAggFuncs = map[string]struct{}{
|
|
ast.AggFuncCount: {},
|
|
ast.AggFuncApproxCountDistinct: {},
|
|
ast.AggFuncApproxPercentile: {},
|
|
ast.AggFuncMax: {},
|
|
ast.AggFuncMin: {},
|
|
ast.AggFuncFirstRow: {},
|
|
ast.WindowFuncNtile: {},
|
|
ast.AggFuncJsonObjectAgg: {},
|
|
}
|
|
|
|
// WrapCastAsDecimalForAggArgs wraps the args of some specific aggregate functions
|
|
// with a cast as decimal function. See issue #19426
|
|
func (a *baseFuncDesc) WrapCastAsDecimalForAggArgs(ctx sessionctx.Context) {
|
|
if a.Name == ast.AggFuncGroupConcat {
|
|
for i := 0; i < len(a.Args)-1; i++ {
|
|
if tp := a.Args[i].GetType(); tp.Tp == mysql.TypeNewDecimal {
|
|
a.Args[i] = expression.BuildCastFunction(ctx, a.Args[i], tp)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// WrapCastForAggArgs wraps the args of an aggregate function with a cast function.
|
|
func (a *baseFuncDesc) WrapCastForAggArgs(ctx sessionctx.Context) {
|
|
if len(a.Args) == 0 {
|
|
return
|
|
}
|
|
if _, ok := noNeedCastAggFuncs[a.Name]; ok {
|
|
return
|
|
}
|
|
var castFunc func(ctx sessionctx.Context, expr expression.Expression) expression.Expression
|
|
switch retTp := a.RetTp; retTp.EvalType() {
|
|
case types.ETInt:
|
|
castFunc = expression.WrapWithCastAsInt
|
|
case types.ETReal:
|
|
castFunc = expression.WrapWithCastAsReal
|
|
case types.ETString:
|
|
castFunc = expression.WrapWithCastAsString
|
|
case types.ETDecimal:
|
|
castFunc = expression.WrapWithCastAsDecimal
|
|
case types.ETDatetime, types.ETTimestamp:
|
|
castFunc = func(ctx sessionctx.Context, expr expression.Expression) expression.Expression {
|
|
return expression.WrapWithCastAsTime(ctx, expr, retTp)
|
|
}
|
|
case types.ETDuration:
|
|
castFunc = expression.WrapWithCastAsDuration
|
|
case types.ETJson:
|
|
castFunc = expression.WrapWithCastAsJSON
|
|
default:
|
|
panic("should never happen in baseFuncDesc.WrapCastForAggArgs")
|
|
}
|
|
for i := range a.Args {
|
|
// Do not cast the second args of these functions, as they are simply non-negative numbers.
|
|
if i == 1 && (a.Name == ast.WindowFuncLead || a.Name == ast.WindowFuncLag || a.Name == ast.WindowFuncNthValue) {
|
|
continue
|
|
}
|
|
a.Args[i] = castFunc(ctx, a.Args[i])
|
|
if a.Name != ast.AggFuncAvg && a.Name != ast.AggFuncSum {
|
|
continue
|
|
}
|
|
// After wrapping cast on the argument, flen etc. may not the same
|
|
// as the type of the aggregation function. The following part set
|
|
// the type of the argument exactly as the type of the aggregation
|
|
// function.
|
|
// Note: If the `Tp` of argument is the same as the `Tp` of the
|
|
// aggregation function, it will not wrap cast function on it
|
|
// internally. The reason of the special handling for `Column` is
|
|
// that the `RetType` of `Column` refers to the `infoschema`, so we
|
|
// need to set a new variable for it to avoid modifying the
|
|
// definition in `infoschema`.
|
|
if col, ok := a.Args[i].(*expression.Column); ok {
|
|
col.RetType = types.NewFieldType(col.RetType.Tp)
|
|
}
|
|
// originTp is used when the the `Tp` of column is TypeFloat32 while
|
|
// the type of the aggregation function is TypeFloat64.
|
|
originTp := a.Args[i].GetType().Tp
|
|
*(a.Args[i].GetType()) = *(a.RetTp)
|
|
a.Args[i].GetType().Tp = originTp
|
|
}
|
|
}
|
|
|