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.
717 lines
16 KiB
717 lines
16 KiB
// Copyright 2015 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 evaluator
|
|
|
|
import (
|
|
"strings"
|
|
|
|
"github.com/juju/errors"
|
|
"github.com/pingcap/tidb/ast"
|
|
"github.com/pingcap/tidb/context"
|
|
"github.com/pingcap/tidb/mysql"
|
|
"github.com/pingcap/tidb/parser/opcode"
|
|
"github.com/pingcap/tidb/sessionctx/variable"
|
|
"github.com/pingcap/tidb/terror"
|
|
"github.com/pingcap/tidb/util/types"
|
|
)
|
|
|
|
// Error instances.
|
|
var (
|
|
ErrInvalidOperation = terror.ClassEvaluator.New(CodeInvalidOperation, "invalid operation")
|
|
)
|
|
|
|
// Error codes.
|
|
const (
|
|
CodeInvalidOperation terror.ErrCode = 1
|
|
)
|
|
|
|
// Eval evaluates an expression to a value.
|
|
func Eval(ctx context.Context, expr ast.ExprNode) (interface{}, error) {
|
|
e := &Evaluator{ctx: ctx}
|
|
expr.Accept(e)
|
|
if e.err != nil {
|
|
return nil, errors.Trace(e.err)
|
|
}
|
|
return expr.GetValue(), nil
|
|
}
|
|
|
|
// EvalBool evalueates an expression to a boolean value.
|
|
func EvalBool(ctx context.Context, expr ast.ExprNode) (bool, error) {
|
|
val, err := Eval(ctx, expr)
|
|
if err != nil {
|
|
return false, errors.Trace(err)
|
|
}
|
|
if val == nil {
|
|
return false, nil
|
|
}
|
|
|
|
i, err := types.ToBool(val)
|
|
if err != nil {
|
|
return false, errors.Trace(err)
|
|
}
|
|
return i != 0, nil
|
|
}
|
|
|
|
func boolToInt64(v bool) int64 {
|
|
if v {
|
|
return int64(1)
|
|
}
|
|
return int64(0)
|
|
}
|
|
|
|
// Evaluator is an ast Visitor that evaluates an expression.
|
|
type Evaluator struct {
|
|
ctx context.Context
|
|
err error
|
|
multipleRows bool
|
|
existRow bool
|
|
}
|
|
|
|
// Enter implements ast.Visitor interface.
|
|
func (e *Evaluator) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
|
|
switch v := in.(type) {
|
|
case *ast.SubqueryExpr:
|
|
if v.Evaluated && !v.UseOuterContext {
|
|
return in, true
|
|
}
|
|
case *ast.PatternInExpr, *ast.CompareSubqueryExpr:
|
|
e.multipleRows = true
|
|
case *ast.ExistsSubqueryExpr:
|
|
e.existRow = true
|
|
}
|
|
return in, false
|
|
}
|
|
|
|
// Leave implements ast.Visitor interface.
|
|
func (e *Evaluator) Leave(in ast.Node) (out ast.Node, ok bool) {
|
|
switch v := in.(type) {
|
|
case *ast.AggregateFuncExpr:
|
|
ok = e.aggregateFunc(v)
|
|
case *ast.BetweenExpr:
|
|
ok = e.between(v)
|
|
case *ast.BinaryOperationExpr:
|
|
ok = e.binaryOperation(v)
|
|
case *ast.CaseExpr:
|
|
ok = e.caseExpr(v)
|
|
case *ast.ColumnName:
|
|
ok = true
|
|
case *ast.ColumnNameExpr:
|
|
ok = e.columnName(v)
|
|
case *ast.CompareSubqueryExpr:
|
|
e.multipleRows = false
|
|
ok = e.compareSubquery(v)
|
|
case *ast.DefaultExpr:
|
|
ok = e.defaultExpr(v)
|
|
case *ast.ExistsSubqueryExpr:
|
|
e.existRow = false
|
|
ok = e.existsSubquery(v)
|
|
case *ast.FuncCallExpr:
|
|
ok = e.funcCall(v)
|
|
case *ast.FuncCastExpr:
|
|
ok = e.funcCast(v)
|
|
case *ast.IsNullExpr:
|
|
ok = e.isNull(v)
|
|
case *ast.IsTruthExpr:
|
|
ok = e.isTruth(v)
|
|
case *ast.ParamMarkerExpr:
|
|
ok = e.paramMarker(v)
|
|
case *ast.ParenthesesExpr:
|
|
ok = e.parentheses(v)
|
|
case *ast.PatternInExpr:
|
|
e.multipleRows = false
|
|
ok = e.patternIn(v)
|
|
case *ast.PatternLikeExpr:
|
|
ok = e.patternLike(v)
|
|
case *ast.PatternRegexpExpr:
|
|
ok = e.patternRegexp(v)
|
|
case *ast.PositionExpr:
|
|
ok = e.position(v)
|
|
case *ast.RowExpr:
|
|
ok = e.row(v)
|
|
case *ast.SubqueryExpr:
|
|
ok = e.subqueryExpr(v)
|
|
case ast.SubqueryExec:
|
|
ok = e.subqueryExec(v)
|
|
case *ast.UnaryOperationExpr:
|
|
ok = e.unaryOperation(v)
|
|
case *ast.ValueExpr:
|
|
ok = true
|
|
case *ast.ValuesExpr:
|
|
ok = e.values(v)
|
|
case *ast.VariableExpr:
|
|
ok = e.variable(v)
|
|
case *ast.WhenClause:
|
|
ok = true
|
|
}
|
|
out = in
|
|
return
|
|
}
|
|
|
|
func (e *Evaluator) between(v *ast.BetweenExpr) bool {
|
|
var l, r ast.ExprNode
|
|
op := opcode.AndAnd
|
|
|
|
if v.Not {
|
|
// v < lv || v > rv
|
|
op = opcode.OrOr
|
|
l = &ast.BinaryOperationExpr{Op: opcode.LT, L: v.Expr, R: v.Left}
|
|
r = &ast.BinaryOperationExpr{Op: opcode.GT, L: v.Expr, R: v.Right}
|
|
} else {
|
|
// v >= lv && v <= rv
|
|
l = &ast.BinaryOperationExpr{Op: opcode.GE, L: v.Expr, R: v.Left}
|
|
r = &ast.BinaryOperationExpr{Op: opcode.LE, L: v.Expr, R: v.Right}
|
|
}
|
|
|
|
ret := &ast.BinaryOperationExpr{Op: op, L: l, R: r}
|
|
ret.Accept(e)
|
|
if e.err != nil {
|
|
return false
|
|
}
|
|
v.SetDatum(*ret.GetDatum())
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) caseExpr(v *ast.CaseExpr) bool {
|
|
tmp := types.NewDatum(boolToInt64(true))
|
|
target := &tmp
|
|
if v.Value != nil {
|
|
target = v.Value.GetDatum()
|
|
}
|
|
if target.Kind() != types.KindNull {
|
|
for _, val := range v.WhenClauses {
|
|
cmp, err := target.CompareDatum(*val.Expr.GetDatum())
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
if cmp == 0 {
|
|
v.SetDatum(*val.Result.GetDatum())
|
|
return true
|
|
}
|
|
}
|
|
}
|
|
if v.ElseClause != nil {
|
|
v.SetDatum(*v.ElseClause.GetDatum())
|
|
} else {
|
|
v.SetNull()
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) columnName(v *ast.ColumnNameExpr) bool {
|
|
v.SetDatum(*v.Refer.Expr.GetDatum())
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) defaultExpr(v *ast.DefaultExpr) bool {
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) compareSubquery(cs *ast.CompareSubqueryExpr) bool {
|
|
lvDatum := cs.L.GetDatum()
|
|
if lvDatum.Kind() == types.KindNull {
|
|
cs.SetNull()
|
|
return true
|
|
}
|
|
lv := lvDatum.GetValue()
|
|
x, err := e.checkResult(cs, lv, cs.R.GetValue().([]interface{}))
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
cs.SetValue(x)
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) checkResult(cs *ast.CompareSubqueryExpr, lv interface{}, result []interface{}) (interface{}, error) {
|
|
if cs.All {
|
|
return e.checkAllResult(cs, lv, result)
|
|
}
|
|
return e.checkAnyResult(cs, lv, result)
|
|
}
|
|
|
|
func (e *Evaluator) checkAllResult(cs *ast.CompareSubqueryExpr, lv interface{}, result []interface{}) (interface{}, error) {
|
|
hasNull := false
|
|
for _, v := range result {
|
|
if v == nil {
|
|
hasNull = true
|
|
continue
|
|
}
|
|
|
|
comRes, err := types.Compare(lv, v)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
|
|
res, err := getCompResult(cs.Op, comRes)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
if !res {
|
|
return false, nil
|
|
}
|
|
}
|
|
if hasNull {
|
|
// If no matched but we get null, return null.
|
|
// Like `insert t (c) values (1),(2),(null)`, then
|
|
// `select 3 > all (select c from t)`, returns null.
|
|
return nil, nil
|
|
}
|
|
return true, nil
|
|
}
|
|
|
|
func (e *Evaluator) checkAnyResult(cs *ast.CompareSubqueryExpr, lv interface{}, result []interface{}) (interface{}, error) {
|
|
hasNull := false
|
|
for _, v := range result {
|
|
if v == nil {
|
|
hasNull = true
|
|
continue
|
|
}
|
|
|
|
comRes, err := types.Compare(lv, v)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
|
|
res, err := getCompResult(cs.Op, comRes)
|
|
if err != nil {
|
|
return nil, errors.Trace(err)
|
|
}
|
|
if res {
|
|
return true, nil
|
|
}
|
|
}
|
|
|
|
if hasNull {
|
|
// If no matched but we get null, return null.
|
|
// Like `insert t (c) values (1),(2),(null)`, then
|
|
// `select 0 > any (select c from t)`, returns null.
|
|
return nil, nil
|
|
}
|
|
|
|
return false, nil
|
|
}
|
|
|
|
func (e *Evaluator) existsSubquery(v *ast.ExistsSubqueryExpr) bool {
|
|
datum := v.Sel.GetDatum()
|
|
if datum.Kind() == types.KindNull {
|
|
v.SetInt64(0)
|
|
return true
|
|
}
|
|
r := datum.GetValue()
|
|
rows, _ := r.([]interface{})
|
|
if len(rows) > 0 {
|
|
v.SetInt64(1)
|
|
} else {
|
|
v.SetInt64(0)
|
|
}
|
|
return true
|
|
}
|
|
|
|
// Evaluate SubqueryExpr.
|
|
// Get the value from v.SubQuery and set it to v.
|
|
func (e *Evaluator) subqueryExpr(v *ast.SubqueryExpr) bool {
|
|
if v.SubqueryExec != nil {
|
|
v.SetDatum(*v.SubqueryExec.GetDatum())
|
|
}
|
|
v.Evaluated = true
|
|
return true
|
|
}
|
|
|
|
// Do the real work to evaluate subquery.
|
|
func (e *Evaluator) subqueryExec(v ast.SubqueryExec) bool {
|
|
rowCount := 2
|
|
if e.multipleRows {
|
|
rowCount = -1
|
|
} else if e.existRow {
|
|
rowCount = 1
|
|
}
|
|
rows, err := v.EvalRows(e.ctx, rowCount)
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
if e.multipleRows || e.existRow {
|
|
v.SetValue(rows)
|
|
return true
|
|
}
|
|
switch len(rows) {
|
|
case 0:
|
|
v.GetDatum().SetNull()
|
|
case 1:
|
|
v.SetValue(rows[0])
|
|
default:
|
|
e.err = errors.New("Subquery returns more than 1 row")
|
|
return false
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) checkInList(not bool, in interface{}, list []interface{}) interface{} {
|
|
hasNull := false
|
|
for _, v := range list {
|
|
if v == nil {
|
|
hasNull = true
|
|
continue
|
|
}
|
|
|
|
r, err := types.Compare(types.Coerce(in, v))
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return nil
|
|
}
|
|
if r == 0 {
|
|
if !not {
|
|
return 1
|
|
}
|
|
return 0
|
|
}
|
|
}
|
|
|
|
if hasNull {
|
|
// if no matched but we got null in In, return null
|
|
// e.g 1 in (null, 2, 3) returns null
|
|
return nil
|
|
}
|
|
if not {
|
|
return 1
|
|
}
|
|
return 0
|
|
}
|
|
|
|
func (e *Evaluator) patternIn(n *ast.PatternInExpr) bool {
|
|
lhs := n.Expr.GetDatum()
|
|
if lhs.Kind() == types.KindNull {
|
|
n.SetNull()
|
|
return true
|
|
}
|
|
if n.Sel == nil {
|
|
values := make([]interface{}, 0, len(n.List))
|
|
for _, ei := range n.List {
|
|
values = append(values, ei.GetValue())
|
|
}
|
|
x := e.checkInList(n.Not, lhs.GetValue(), values)
|
|
if e.err != nil {
|
|
return false
|
|
}
|
|
n.SetValue(x)
|
|
return true
|
|
}
|
|
se := n.Sel.(*ast.SubqueryExpr)
|
|
sel := se.SubqueryExec
|
|
|
|
res := sel.GetValue().([]interface{})
|
|
x := e.checkInList(n.Not, lhs.GetValue(), res)
|
|
if e.err != nil {
|
|
return false
|
|
}
|
|
n.SetValue(x)
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) isNull(v *ast.IsNullExpr) bool {
|
|
var boolVal bool
|
|
if v.Expr.GetDatum().Kind() == types.KindNull {
|
|
boolVal = true
|
|
}
|
|
if v.Not {
|
|
boolVal = !boolVal
|
|
}
|
|
v.SetInt64(boolToInt64(boolVal))
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) isTruth(v *ast.IsTruthExpr) bool {
|
|
var boolVal bool
|
|
datum := v.Expr.GetDatum()
|
|
if datum.Kind() != types.KindNull {
|
|
ival, err := datum.ToBool()
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
if ival == v.True {
|
|
boolVal = true
|
|
}
|
|
}
|
|
if v.Not {
|
|
boolVal = !boolVal
|
|
}
|
|
v.GetDatum().SetInt64(boolToInt64(boolVal))
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) paramMarker(v *ast.ParamMarkerExpr) bool {
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) parentheses(v *ast.ParenthesesExpr) bool {
|
|
v.SetDatum(*v.Expr.GetDatum())
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) position(v *ast.PositionExpr) bool {
|
|
v.SetDatum(*v.Refer.Expr.GetDatum())
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) row(v *ast.RowExpr) bool {
|
|
row := make([]interface{}, 0, len(v.Values))
|
|
for _, val := range v.Values {
|
|
row = append(row, val.GetValue())
|
|
}
|
|
v.SetValue(row)
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) unaryOperation(u *ast.UnaryOperationExpr) bool {
|
|
defer func() {
|
|
if er := recover(); er != nil {
|
|
e.err = errors.Errorf("%v", er)
|
|
}
|
|
}()
|
|
aDatum := u.V.GetDatum()
|
|
if aDatum.Kind() == types.KindNull {
|
|
u.SetNull()
|
|
return true
|
|
}
|
|
switch op := u.Op; op {
|
|
case opcode.Not:
|
|
n, err := aDatum.ToBool()
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
} else if n == 0 {
|
|
u.SetInt64(1)
|
|
} else {
|
|
u.SetInt64(0)
|
|
}
|
|
case opcode.BitNeg:
|
|
// for bit operation, we will use int64 first, then return uint64
|
|
n, err := aDatum.ToInt64()
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
u.SetUint64(uint64(^n))
|
|
case opcode.Plus:
|
|
switch aDatum.Kind() {
|
|
case types.KindInt64,
|
|
types.KindUint64,
|
|
types.KindFloat64,
|
|
types.KindFloat32,
|
|
types.KindMysqlDuration,
|
|
types.KindMysqlTime,
|
|
types.KindString,
|
|
types.KindMysqlDecimal,
|
|
types.KindBytes,
|
|
types.KindMysqlHex,
|
|
types.KindMysqlBit,
|
|
types.KindMysqlEnum,
|
|
types.KindMysqlSet:
|
|
u.SetDatum(*aDatum)
|
|
default:
|
|
e.err = ErrInvalidOperation
|
|
return false
|
|
}
|
|
case opcode.Minus:
|
|
switch aDatum.Kind() {
|
|
case types.KindInt64:
|
|
u.SetInt64(-aDatum.GetInt64())
|
|
case types.KindUint64:
|
|
u.SetInt64(-int64(aDatum.GetUint64()))
|
|
case types.KindFloat64:
|
|
u.SetFloat64(-aDatum.GetFloat64())
|
|
case types.KindFloat32:
|
|
u.SetFloat32(-aDatum.GetFloat32())
|
|
case types.KindMysqlDuration:
|
|
u.SetValue(mysql.ZeroDecimal.Sub(aDatum.GetMysqlDuration().ToNumber()))
|
|
case types.KindMysqlTime:
|
|
u.SetValue(mysql.ZeroDecimal.Sub(aDatum.GetMysqlTime().ToNumber()))
|
|
case types.KindString:
|
|
f, err := types.StrToFloat(aDatum.GetString())
|
|
e.err = errors.Trace(err)
|
|
u.SetFloat64(-f)
|
|
case types.KindMysqlDecimal:
|
|
f, _ := aDatum.GetMysqlDecimal().Float64()
|
|
u.SetValue(mysql.NewDecimalFromFloat(-f))
|
|
case types.KindBytes:
|
|
f, err := types.StrToFloat(string(aDatum.GetBytes()))
|
|
e.err = errors.Trace(err)
|
|
u.SetFloat64(-f)
|
|
case types.KindMysqlHex:
|
|
u.SetFloat64(-aDatum.GetMysqlHex().ToNumber())
|
|
case types.KindMysqlBit:
|
|
u.SetFloat64(-aDatum.GetMysqlBit().ToNumber())
|
|
case types.KindMysqlEnum:
|
|
u.SetFloat64(-aDatum.GetMysqlEnum().ToNumber())
|
|
case types.KindMysqlSet:
|
|
u.SetFloat64(-aDatum.GetMysqlSet().ToNumber())
|
|
default:
|
|
e.err = ErrInvalidOperation
|
|
return false
|
|
}
|
|
default:
|
|
e.err = ErrInvalidOperation
|
|
return false
|
|
}
|
|
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) values(v *ast.ValuesExpr) bool {
|
|
v.SetDatum(*v.Column.GetDatum())
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) variable(v *ast.VariableExpr) bool {
|
|
name := strings.ToLower(v.Name)
|
|
sessionVars := variable.GetSessionVars(e.ctx)
|
|
globalVars := variable.GetGlobalVarAccessor(e.ctx)
|
|
if !v.IsSystem {
|
|
// user vars
|
|
if value, ok := sessionVars.Users[name]; ok {
|
|
v.SetString(value)
|
|
return true
|
|
}
|
|
// select null user vars is permitted.
|
|
v.SetNull()
|
|
return true
|
|
}
|
|
|
|
_, ok := variable.SysVars[name]
|
|
if !ok {
|
|
// select null sys vars is not permitted
|
|
e.err = variable.UnknownSystemVar.Gen("Unknown system variable '%s'", name)
|
|
return false
|
|
}
|
|
|
|
if !v.IsGlobal {
|
|
if value, ok := sessionVars.Systems[name]; ok {
|
|
v.SetString(value)
|
|
return true
|
|
}
|
|
}
|
|
|
|
value, err := globalVars.GetGlobalSysVar(e.ctx, name)
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
|
|
v.SetString(value)
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) funcCall(v *ast.FuncCallExpr) bool {
|
|
of, ok := OldFuncs[v.FnName.L]
|
|
if ok {
|
|
if len(v.Args) < of.MinArgs || (of.MaxArgs != -1 && len(v.Args) > of.MaxArgs) {
|
|
e.err = ErrInvalidOperation.Gen("number of function arguments must in [%d, %d].", of.MinArgs, of.MaxArgs)
|
|
return false
|
|
}
|
|
a := make([]interface{}, len(v.Args))
|
|
for i, arg := range v.Args {
|
|
a[i] = arg.GetValue()
|
|
}
|
|
val, err := of.F(a, e.ctx)
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
v.SetValue(val)
|
|
return true
|
|
}
|
|
f, ok := Funcs[v.FnName.L]
|
|
if !ok {
|
|
e.err = ErrInvalidOperation.Gen("unknown function %s", v.FnName.O)
|
|
return false
|
|
}
|
|
if len(v.Args) < f.MinArgs || (f.MaxArgs != -1 && len(v.Args) > f.MaxArgs) {
|
|
e.err = ErrInvalidOperation.Gen("number of function arguments must in [%d, %d].", f.MinArgs, f.MaxArgs)
|
|
return false
|
|
}
|
|
a := make([]types.Datum, len(v.Args))
|
|
for i, arg := range v.Args {
|
|
a[i] = *arg.GetDatum()
|
|
}
|
|
val, err := f.F(a, e.ctx)
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
v.SetDatum(val)
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) funcCast(v *ast.FuncCastExpr) bool {
|
|
value := v.Expr.GetValue()
|
|
// Casting nil to any type returns null
|
|
if value == nil {
|
|
v.SetNull()
|
|
return true
|
|
}
|
|
var err error
|
|
value, err = types.Cast(value, v.Tp)
|
|
if err != nil {
|
|
e.err = errors.Trace(err)
|
|
return false
|
|
}
|
|
v.SetValue(value)
|
|
return true
|
|
}
|
|
|
|
func (e *Evaluator) aggregateFunc(v *ast.AggregateFuncExpr) bool {
|
|
name := strings.ToLower(v.F)
|
|
switch name {
|
|
case ast.AggFuncAvg:
|
|
e.evalAggAvg(v)
|
|
case ast.AggFuncCount:
|
|
e.evalAggCount(v)
|
|
case ast.AggFuncFirstRow, ast.AggFuncMax, ast.AggFuncMin, ast.AggFuncSum:
|
|
e.evalAggSetValue(v)
|
|
case ast.AggFuncGroupConcat:
|
|
e.evalAggGroupConcat(v)
|
|
}
|
|
return e.err == nil
|
|
}
|
|
|
|
func (e *Evaluator) evalAggCount(v *ast.AggregateFuncExpr) {
|
|
ctx := v.GetContext()
|
|
v.SetInt64(ctx.Count)
|
|
}
|
|
|
|
func (e *Evaluator) evalAggSetValue(v *ast.AggregateFuncExpr) {
|
|
ctx := v.GetContext()
|
|
v.SetValue(ctx.Value)
|
|
}
|
|
|
|
func (e *Evaluator) evalAggAvg(v *ast.AggregateFuncExpr) {
|
|
ctx := v.GetContext()
|
|
switch x := ctx.Value.(type) {
|
|
case float64:
|
|
ctx.Value = x / float64(ctx.Count)
|
|
case mysql.Decimal:
|
|
ctx.Value = x.Div(mysql.NewDecimalFromUint(uint64(ctx.Count), 0))
|
|
}
|
|
v.SetValue(ctx.Value)
|
|
}
|
|
|
|
func (e *Evaluator) evalAggGroupConcat(v *ast.AggregateFuncExpr) {
|
|
ctx := v.GetContext()
|
|
if ctx.Buffer != nil {
|
|
v.SetValue(ctx.Buffer.String())
|
|
} else {
|
|
v.SetValue(nil)
|
|
}
|
|
}
|