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Merge pull request #157 from huandu/feature/cte
Support CTE (Common Table Expression)
2 parents 9fc30d9 + a0af5e4 commit 3282717

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‎README.md‎

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@@ -81,6 +81,7 @@ This package includes following pre-defined builders so far. API document and ex
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- [UpdateBuilder](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#UpdateBuilder): Builder for UPDATE.
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- [DeleteBuilder](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#DeleteBuilder): Builder for DELETE.
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- [UnionBuilder](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#UnionBuilder): Builder for UNION and UNION ALL.
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- [CTEBuilder](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#CTEBuilder): Builder for Common Table Expression (CTE), e.g. `WITH name (col1, col2) AS (SELECT ...)`.
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- [Buildf](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#Buildf): Freestyle builder using `fmt.Sprintf`-like syntax.
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- [Build](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#Build): Advanced freestyle builder using special syntax defined in [Args#Compile](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#Args.Compile).
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- [BuildNamed](https://pkg.go.dev/github.com/huandu/go-sqlbuilder#BuildNamed): Advanced freestyle builder using `${key}` to refer the value of a map by key.

‎cte.go‎

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// Copyright 2024 Huan Du. All rights reserved.
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// Licensed under the MIT license that can be found in the LICENSE file.
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package sqlbuilder
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const (
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cteMarkerInit injectionMarker = iota
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cteMarkerAfterWith
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)
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// With creates a new CTE builder with default flavor.
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func With(tables ...*CTETableBuilder) *CTEBuilder {
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return DefaultFlavor.NewCTEBuilder().With(tables...)
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}
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func newCTEBuilder() *CTEBuilder {
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return &CTEBuilder{
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args: &Args{},
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injection: newInjection(),
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}
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}
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// CTEBuilder is a CTE (Common Table Expression) builder.
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type CTEBuilder struct {
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tableNames []string
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tableBuilderVars []string
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args *Args
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injection *injection
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marker injectionMarker
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}
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var _ Builder = new(CTEBuilder)
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// With sets the CTE name and columns.
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func (cteb *CTEBuilder) With(tables ...*CTETableBuilder) *CTEBuilder {
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tableNames := make([]string, 0, len(tables))
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tableBuilderVars := make([]string, 0, len(tables))
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for _, table := range tables {
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tableNames = append(tableNames, table.TableName())
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tableBuilderVars = append(tableBuilderVars, cteb.args.Add(table))
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}
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cteb.tableNames = tableNames
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cteb.tableBuilderVars = tableBuilderVars
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cteb.marker = cteMarkerAfterWith
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return cteb
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}
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// Select creates a new SelectBuilder to build a SELECT statement using this CTE.
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func (cteb *CTEBuilder) Select(col ...string) *SelectBuilder {
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sb := cteb.args.Flavor.NewSelectBuilder()
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return sb.With(cteb).Select(col...)
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}
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// String returns the compiled CTE string.
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func (cteb *CTEBuilder) String() string {
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sql, _ := cteb.Build()
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return sql
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}
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// Build returns compiled CTE string and args.
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func (cteb *CTEBuilder) Build() (sql string, args []interface{}) {
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return cteb.BuildWithFlavor(cteb.args.Flavor)
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}
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// BuildWithFlavor builds a CTE with the specified flavor and initial arguments.
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func (cteb *CTEBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{}) (sql string, args []interface{}) {
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buf := newStringBuilder()
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cteb.injection.WriteTo(buf, cteMarkerInit)
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if len(cteb.tableBuilderVars) > 0 {
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buf.WriteLeadingString("WITH ")
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buf.WriteStrings(cteb.tableBuilderVars, ", ")
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}
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cteb.injection.WriteTo(buf, cteMarkerAfterWith)
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return cteb.args.CompileWithFlavor(buf.String(), flavor, initialArg...)
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}
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// SetFlavor sets the flavor of compiled sql.
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func (cteb *CTEBuilder) SetFlavor(flavor Flavor) (old Flavor) {
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old = cteb.args.Flavor
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cteb.args.Flavor = flavor
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return
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}
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// SQL adds an arbitrary sql to current position.
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func (cteb *CTEBuilder) SQL(sql string) *CTEBuilder {
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cteb.injection.SQL(cteb.marker, sql)
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return cteb
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}
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// TableNames returns all table names in a CTE.
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func (cteb *CTEBuilder) TableNames() []string {
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return cteb.tableNames
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}

‎cte_test.go‎

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// Copyright 2024 Huan Du. All rights reserved.
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// Licensed under the MIT license that can be found in the LICENSE file.
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package sqlbuilder
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import (
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"fmt"
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"testing"
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"github.com/huandu/go-assert"
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)
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func ExampleWith() {
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sb := With(
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CTETable("users", "id", "name").As(
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Select("id", "name").From("users").Where("name IS NOT NULL"),
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),
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CTETable("devices").As(
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Select("device_id").From("devices"),
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),
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).Select("users.id", "orders.id", "devices.device_id").Join(
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"orders",
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"users.id = orders.user_id",
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"devices.device_id = orders.device_id",
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)
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fmt.Println(sb)
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// Output:
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// WITH users (id, name) AS (SELECT id, name FROM users WHERE name IS NOT NULL), devices AS (SELECT device_id FROM devices) SELECT users.id, orders.id, devices.device_id FROM users, devices JOIN orders ON users.id = orders.user_id AND devices.device_id = orders.device_id
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}
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func ExampleCTEBuilder() {
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usersBuilder := Select("id", "name", "level").From("users")
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usersBuilder.Where(
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usersBuilder.GreaterEqualThan("level", 10),
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)
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cteb := With(
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CTETable("valid_users").As(usersBuilder),
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)
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fmt.Println(cteb)
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sb := Select("valid_users.id", "valid_users.name", "orders.id").With(cteb)
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sb.Join("orders", "valid_users.id = orders.user_id")
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sb.Where(
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sb.LessEqualThan("orders.price", 200),
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"valid_users.level < orders.min_level",
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).OrderBy("orders.price").Desc()
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sql, args := sb.Build()
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fmt.Println(sql)
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fmt.Println(args)
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// Output:
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// WITH valid_users AS (SELECT id, name, level FROM users WHERE level >= ?)
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// WITH valid_users AS (SELECT id, name, level FROM users WHERE level >= ?) SELECT valid_users.id, valid_users.name, orders.id FROM valid_users JOIN orders ON valid_users.id = orders.user_id WHERE orders.price <= ? AND valid_users.level < orders.min_level ORDER BY orders.price DESC
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// [10 200]
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}
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func TestCTEBuilder(t *testing.T) {
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a := assert.New(t)
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cteb := newCTEBuilder()
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ctetb := newCTETableBuilder()
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cteb.SQL("/* init */")
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cteb.With(ctetb)
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cteb.SQL("/* after with */")
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ctetb.SQL("/* table init */")
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ctetb.Table("t", "a", "b")
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ctetb.SQL("/* after table */")
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ctetb.As(Select("a", "b").From("t"))
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ctetb.SQL("/* after table as */")
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sql, args := cteb.Build()
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a.Equal(sql, "/* init */ WITH /* table init */ t (a, b) /* after table */ AS (SELECT a, b FROM t) /* after table as */ /* after with */")
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a.Assert(args == nil)
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sql = ctetb.String()
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a.Equal(sql, "/* table init */ t (a, b) /* after table */ AS (SELECT a, b FROM t) /* after table as */")
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}

‎ctetable.go‎

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// Copyright 2024 Huan Du. All rights reserved.
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// Licensed under the MIT license that can be found in the LICENSE file.
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4+
package sqlbuilder
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const (
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cteTableMarkerInit injectionMarker = iota
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cteTableMarkerAfterTable
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cteTableMarkerAfterAs
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)
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// CTETable creates a new CTE table builder with default flavor.
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func CTETable(name string, cols ...string) *CTETableBuilder {
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return DefaultFlavor.NewCTETableBuilder().Table(name, cols...)
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}
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func newCTETableBuilder() *CTETableBuilder {
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return &CTETableBuilder{
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args: &Args{},
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injection: newInjection(),
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}
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}
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// CTETableBuilder is a builder to build one table in CTE (Common Table Expression).
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type CTETableBuilder struct {
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name string
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cols []string
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builderVar string
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args *Args
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injection *injection
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marker injectionMarker
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}
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// Table sets the table name and columns in a CTE table.
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func (ctetb *CTETableBuilder) Table(name string, cols ...string) *CTETableBuilder {
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ctetb.name = name
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ctetb.cols = cols
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ctetb.marker = cteTableMarkerAfterTable
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return ctetb
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}
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// As sets the builder to select data.
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func (ctetb *CTETableBuilder) As(builder Builder) *CTETableBuilder {
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ctetb.builderVar = ctetb.args.Add(builder)
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ctetb.marker = cteTableMarkerAfterAs
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return ctetb
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}
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// String returns the compiled CTE string.
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func (ctetb *CTETableBuilder) String() string {
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sql, _ := ctetb.Build()
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return sql
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}
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// Build returns compiled CTE string and args.
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func (ctetb *CTETableBuilder) Build() (sql string, args []interface{}) {
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return ctetb.BuildWithFlavor(ctetb.args.Flavor)
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}
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// BuildWithFlavor builds a CTE with the specified flavor and initial arguments.
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func (ctetb *CTETableBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{}) (sql string, args []interface{}) {
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buf := newStringBuilder()
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ctetb.injection.WriteTo(buf, cteTableMarkerInit)
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if ctetb.name != "" {
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buf.WriteLeadingString(ctetb.name)
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if len(ctetb.cols) > 0 {
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buf.WriteLeadingString("(")
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buf.WriteStrings(ctetb.cols, ", ")
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buf.WriteString(")")
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}
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ctetb.injection.WriteTo(buf, cteTableMarkerAfterTable)
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}
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if ctetb.builderVar != "" {
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buf.WriteLeadingString("AS (")
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buf.WriteString(ctetb.builderVar)
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buf.WriteRune(')')
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ctetb.injection.WriteTo(buf, cteTableMarkerAfterAs)
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}
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return ctetb.args.CompileWithFlavor(buf.String(), flavor, initialArg...)
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}
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// SetFlavor sets the flavor of compiled sql.
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func (ctetb *CTETableBuilder) SetFlavor(flavor Flavor) (old Flavor) {
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old = ctetb.args.Flavor
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ctetb.args.Flavor = flavor
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return
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}
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// SQL adds an arbitrary sql to current position.
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func (ctetb *CTETableBuilder) SQL(sql string) *CTETableBuilder {
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ctetb.injection.SQL(ctetb.marker, sql)
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return ctetb
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}
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// TableName returns the CTE table name.
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func (ctetb *CTETableBuilder) TableName() string {
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return ctetb.name
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}

‎flavor.go‎

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@@ -141,6 +141,20 @@ func (f Flavor) NewUnionBuilder() *UnionBuilder {
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return b
142142
}
143143

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// NewCTEBuilder creates a new CTE builder with flavor.
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func (f Flavor) NewCTEBuilder() *CTEBuilder {
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b := newCTEBuilder()
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b.SetFlavor(f)
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return b
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}
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// NewCTETableBuilder creates a new CTE table builder with flavor.
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func (f Flavor) NewCTETableBuilder() *CTETableBuilder {
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b := newCTETableBuilder()
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b.SetFlavor(f)
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return b
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}
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// Quote adds quote for name to make sure the name can be used safely
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// as table name or field name.
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//

‎select.go‎

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@@ -11,6 +11,7 @@ import (
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const (
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selectMarkerInit injectionMarker = iota
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selectMarkerAfterWith
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selectMarkerAfterSelect
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selectMarkerAfterFrom
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selectMarkerAfterJoin
@@ -65,6 +66,7 @@ type SelectBuilder struct {
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whereClauseProxy *whereClauseProxy
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whereClauseExpr string
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cteBuilder string
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distinct bool
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tables []string
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selectCols []string
@@ -92,6 +94,14 @@ func Select(col ...string) *SelectBuilder {
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return DefaultFlavor.NewSelectBuilder().Select(col...)
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}
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// With sets WITH clause (the Common Table Expression) before SELECT.
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func (sb *SelectBuilder) With(builder *CTEBuilder) *SelectBuilder {
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sb.marker = selectMarkerAfterWith
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sb.cteBuilder = sb.Var(builder)
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sb.tables = builder.TableNames()
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return sb
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}
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// Select sets columns in SELECT.
96106
func (sb *SelectBuilder) Select(col ...string) *SelectBuilder {
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sb.selectCols = col
@@ -269,6 +279,11 @@ func (sb *SelectBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{
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270280
oraclePage := flavor == Oracle && (sb.limit >= 0 || sb.offset >= 0)
271281

282+
if sb.cteBuilder != "" {
283+
buf.WriteLeadingString(sb.cteBuilder)
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sb.injection.WriteTo(buf, selectMarkerAfterWith)
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}
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if len(sb.selectCols) > 0 {
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buf.WriteLeadingString("SELECT ")
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‎struct_test.go‎

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@@ -638,9 +638,7 @@ func ExampleStruct_buildDELETE() {
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// Prepare DELETE query.
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user := &User{
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ID: 1234,
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Name: "Huan Du",
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Status: 1,
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ID: 1234,
644642
}
645643
b := userStruct.DeleteFrom("user")
646644
b.Where(b.Equal("id", user.ID))

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