-
-
Notifications
You must be signed in to change notification settings - Fork 199
/
select.go
233 lines (206 loc) · 7.24 KB
/
select.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
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
// Copyright 2023 Dolthub, 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,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package planbuilder
import (
"fmt"
ast "github.com/dolthub/vitess/go/vt/sqlparser"
"github.com/dolthub/go-mysql-server/sql"
"github.com/dolthub/go-mysql-server/sql/expression"
"github.com/dolthub/go-mysql-server/sql/mysql_db"
"github.com/dolthub/go-mysql-server/sql/plan"
"github.com/dolthub/go-mysql-server/sql/types"
)
func (b *Builder) buildSelectStmt(inScope *scope, s ast.SelectStatement) (outScope *scope) {
switch s := s.(type) {
case *ast.Select:
if s.With != nil {
cteScope := b.buildWith(inScope, s.With)
return b.buildSelect(cteScope, s)
}
return b.buildSelect(inScope, s)
case *ast.SetOp:
if s.With != nil {
cteScope := b.buildWith(inScope, s.With)
return b.buildSetOp(cteScope, s)
}
return b.buildSetOp(inScope, s)
case *ast.ParenSelect:
return b.buildSelectStmt(inScope, s.Select)
default:
b.handleErr(fmt.Errorf("unknown select statement %T", s))
}
return
}
func (b *Builder) buildSelect(inScope *scope, s *ast.Select) (outScope *scope) {
// General order of binding:
// 1) Get definitions in FROM.
// 2) Build WHERE, which can only reference FROM columns.
// 3) Bookkeep aggregation/window function usage in higher-scopes
// (GROUP BY, WINDOW, HAVING, SELECT, ORDER BY).
// 4) Construct either i) aggregation, ii) window, or iii) projection over
// FROM clause providing expressions used in (2) (including aliases).
// 5) Build top-level scopes, replacing aggregation and aliases with
// projections from (4).
// 6) Finish with final target projections.
fromScope := b.buildFrom(inScope, s.From)
if cn, ok := fromScope.node.(sql.CommentedNode); ok && len(s.Comments) > 0 {
fromScope.node = cn.WithComment(string(s.Comments[0]))
}
// Resolve and fold named window definitions
b.buildNamedWindows(fromScope, s.Window)
b.buildWhere(fromScope, s.Where)
// select *, (SELECT t2.i) from t1 left join using t2 on i;
// select t1.*, t2.*, t2.* from ...
//
projScope := fromScope.push()
// Aggregates in select list added to fromScope.groupBy.outCols.
// Args to aggregates added to fromScope.groupBy.inCols.
b.analyzeProjectionList(fromScope, projScope, s.SelectExprs)
// Find aggregations in order by
orderByScope := b.analyzeOrderBy(fromScope, projScope, s.OrderBy)
// Find aggregations in having
b.analyzeHaving(fromScope, projScope, s.Having)
// At this point we've recorded dependencies for higher-level scopes,
// so we can build the FROM clause
if b.needsAggregation(fromScope, s) {
groupingCols := b.buildGroupingCols(fromScope, projScope, s.GroupBy, s.SelectExprs)
outScope = b.buildAggregation(fromScope, projScope, groupingCols)
} else if fromScope.windowFuncs != nil {
outScope = b.buildWindow(fromScope, projScope)
} else {
outScope = b.buildInnerProj(fromScope, projScope)
}
// At this point, we've combined table relations, performed aggregations,
// and projected aliases used in higher-level clauses. Aliases and agg
// expressions in higher level scopes will be replaced with GetField
// references.
b.buildHaving(fromScope, projScope, outScope, s.Having)
b.buildOrderBy(outScope, orderByScope)
// Last level projection restricts outputs to target projections.
b.buildProjection(outScope, projScope)
outScope = projScope
b.buildDistinct(outScope, s.QueryOpts.Distinct)
// OFFSET and LIMIT are last
offset := b.buildOffset(outScope, s.Limit)
if offset != nil {
outScope.node = plan.NewOffset(offset, outScope.node)
}
limit := b.buildLimit(outScope, s.Limit)
if limit != nil {
l := plan.NewLimit(limit, outScope.node)
l.CalcFoundRows = s.QueryOpts.SQLCalcFoundRows
outScope.node = l
}
return
}
func (b *Builder) buildLimit(inScope *scope, limit *ast.Limit) sql.Expression {
if limit != nil {
return b.buildLimitVal(inScope, limit.Rowcount)
}
return nil
}
func (b *Builder) buildOffset(inScope *scope, limit *ast.Limit) sql.Expression {
if limit != nil && limit.Offset != nil {
e := b.buildLimitVal(inScope, limit.Offset)
if lit, ok := e.(*expression.Literal); ok {
// Check if offset starts at 0, if so, we can just remove the offset node.
// Only cast to int8, as a larger int type just means a non-zero offset.
if val, err := lit.Eval(b.ctx, nil); err == nil {
if v, ok := val.(int64); ok && v == 0 {
return nil
}
}
}
return e
}
return nil
}
// buildLimitVal resolves a literal numeric type or a numeric
// prodecure parameter
func (b *Builder) buildLimitVal(inScope *scope, e ast.Expr) sql.Expression {
switch e := e.(type) {
case *ast.ColName:
if inScope.procActive() {
if col, ok := inScope.proc.GetVar(e.String()); ok {
// proc param is OK
if pp, ok := col.scalarGf().(*expression.ProcedureParam); ok {
if !pp.Type().Promote().Equals(types.Int64) && !pp.Type().Promote().Equals(types.Uint64) {
err := fmt.Errorf("the variable '%s' has a non-integer based type: %s", pp.Name(), pp.Type().String())
b.handleErr(err)
}
return pp
}
}
}
err := fmt.Errorf("limit expression expected to be numeric or prodecure parameter, found invalid column: %s", e.String())
b.handleErr(err)
default:
l := b.buildScalar(inScope, e)
return b.typeCoerceLiteral(l)
}
return nil
}
func (b *Builder) typeCoerceLiteral(e sql.Expression) sql.Expression {
// todo this should be in a module that can generically coerce to a type or type class
switch e := e.(type) {
case *expression.Literal:
val, _, err := types.Int64.Convert(e.Value())
if err != nil {
err = fmt.Errorf("%s: %w", err.Error(), sql.ErrInvalidTypeForLimit.New(types.Int64, e.Type()))
}
return expression.NewLiteral(val, types.Int64)
case *expression.BindVar:
return e
default:
err := sql.ErrInvalidTypeForLimit.New(expression.Literal{}, e)
b.handleErr(err)
}
return nil
}
// buildDistinct creates a new plan.Distinct node if the query has a DISTINCT option.
// If the query has both DISTINCT and ALL, an error is returned.
func (b *Builder) buildDistinct(inScope *scope, distinct bool) {
if distinct {
inScope.node = plan.NewDistinct(inScope.node)
}
}
func (b *Builder) currentDb() sql.Database {
if b.currentDatabase == nil {
if b.ctx.GetCurrentDatabase() == "" {
err := sql.ErrNoDatabaseSelected.New()
b.handleErr(err)
}
database, err := b.cat.Database(b.ctx, b.ctx.GetCurrentDatabase())
if err != nil {
b.handleErr(err)
}
if privilegedDatabase, ok := database.(mysql_db.PrivilegedDatabase); ok {
database = privilegedDatabase.Unwrap()
}
b.currentDatabase = database
}
return b.currentDatabase
}
func (b *Builder) renameSource(scope *scope, table string, cols []string) {
if table != "" {
scope.setTableAlias(table)
}
if len(cols) > 0 {
scope.setColAlias(cols)
}
for i, c := range scope.cols {
c.scalar = nil
scope.cols[i] = c
}
}