// Copyright 2017 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 ( "github.com/pingcap/tidb/sessionctx/stmtctx" "github.com/pingcap/tidb/types" "github.com/pingcap/tidb/util/chunk" ) type countFunction struct { aggFunction } // Update implements Aggregation interface. func (cf *countFunction) Update(evalCtx *AggEvaluateContext, sc *stmtctx.StatementContext, row chunk.Row) error { var datumBuf []types.Datum if cf.HasDistinct { datumBuf = make([]types.Datum, 0, len(cf.Args)) } for _, a := range cf.Args { value, err := a.Eval(row) if err != nil { return err } if value.IsNull() { return nil } if cf.Mode == FinalMode || cf.Mode == Partial2Mode { evalCtx.Count += value.GetInt64() } if cf.HasDistinct { datumBuf = append(datumBuf, value) } } if cf.HasDistinct { d, err := evalCtx.DistinctChecker.Check(datumBuf) if err != nil { return err } if !d { return nil } } if cf.Mode == CompleteMode || cf.Mode == Partial1Mode { evalCtx.Count++ } return nil } func (cf *countFunction) ResetContext(sc *stmtctx.StatementContext, evalCtx *AggEvaluateContext) { if cf.HasDistinct { evalCtx.DistinctChecker = createDistinctChecker(sc) } evalCtx.Count = 0 } // GetResult implements Aggregation interface. func (cf *countFunction) GetResult(evalCtx *AggEvaluateContext) (d types.Datum) { d.SetInt64(evalCtx.Count) return d } // GetPartialResult implements Aggregation interface. func (cf *countFunction) GetPartialResult(evalCtx *AggEvaluateContext) []types.Datum { return []types.Datum{cf.GetResult(evalCtx)} }