/
concat.go
127 lines (116 loc) · 3.19 KB
/
concat.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
// 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 (
"bytes"
"fmt"
"github.com/juju/errors"
"github.com/pingcap/tidb/mysql"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/util/charset"
"github.com/pingcap/tidb/util/types"
)
type concatFunction struct {
aggFunction
separator string
sepInited bool
}
// Clone implements Aggregation interface.
func (cf *concatFunction) Clone() Aggregation {
nf := *cf
for i, arg := range cf.Args {
nf.Args[i] = arg.Clone()
}
return &nf
}
// GetType implements Aggregation interface.
func (cf *concatFunction) GetType() *types.FieldType {
retType := types.NewFieldType(mysql.TypeVarString)
retType.Charset = charset.CharsetUTF8
retType.Collate = charset.CollationUTF8
retType.Flen, retType.Decimal = mysql.MaxBlobWidth, 0
return retType
}
func (cf *concatFunction) writeValue(ctx *AggEvaluateContext, val types.Datum) {
if val.Kind() == types.KindBytes {
ctx.Buffer.Write(val.GetBytes())
} else {
ctx.Buffer.WriteString(fmt.Sprintf("%v", val.GetValue()))
}
}
func (cf *concatFunction) initSeparator(sc *variable.StatementContext, row []types.Datum) error {
sepArg := cf.Args[len(cf.Args)-1]
sep, isNull, err := sepArg.EvalString(row, sc)
if err != nil {
return errors.Trace(err)
}
if isNull {
return errors.Errorf("Invalid separator argument.")
}
cf.separator = sep
cf.Args = cf.Args[:len(cf.Args)-1]
return nil
}
// Update implements Aggregation interface.
func (cf *concatFunction) Update(ctx *AggEvaluateContext, sc *variable.StatementContext, row []types.Datum) error {
datumBuf := make([]types.Datum, 0, len(cf.Args))
if !cf.sepInited {
err := cf.initSeparator(sc, row)
if err != nil {
return errors.Trace(err)
}
cf.sepInited = true
}
for _, a := range cf.Args {
value, err := a.Eval(row)
if err != nil {
return errors.Trace(err)
}
if value.GetValue() == nil {
return nil
}
datumBuf = append(datumBuf, value)
}
if cf.Distinct {
d, err := ctx.DistinctChecker.Check(datumBuf)
if err != nil {
return errors.Trace(err)
}
if !d {
return nil
}
}
if ctx.Buffer == nil {
ctx.Buffer = &bytes.Buffer{}
} else {
ctx.Buffer.WriteString(cf.separator)
}
for _, val := range datumBuf {
cf.writeValue(ctx, val)
}
// TODO: if total length is greater than global var group_concat_max_len, truncate it.
return nil
}
// GetResult implements Aggregation interface.
func (cf *concatFunction) GetResult(ctx *AggEvaluateContext) (d types.Datum) {
if ctx.Buffer != nil {
d.SetString(ctx.Buffer.String())
} else {
d.SetNull()
}
return d
}
// GetPartialResult implements Aggregation interface.
func (cf *concatFunction) GetPartialResult(ctx *AggEvaluateContext) []types.Datum {
return []types.Datum{cf.GetResult(ctx)}
}