/
union.go
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/
union.go
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// Copyright 2012, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in licenses/BSD-vitess.txt.
// Portions of this file are additionally subject to the following
// license and copyright.
//
// Copyright 2015 The Cockroach Authors.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0, included in the file
// licenses/APL.txt.
// This code was derived from https://github.com/youtube/vitess.
package ast
import "fmt"
// UnionClause represents a UNION statement.
type UnionClause struct {
Type UnionType
Left, Right *Select
All bool
}
// UnionType represents one of the three set operations in sql.
type UnionType int
// Union.Type
const (
UnionOp UnionType = iota
IntersectOp
ExceptOp
)
var unionTypeName = [...]string{
UnionOp: "UNION",
IntersectOp: "INTERSECT",
ExceptOp: "EXCEPT",
}
func (i UnionType) String() string {
if i < 0 || i > UnionType(len(unionTypeName)-1) {
return fmt.Sprintf("UnionType(%d)", i)
}
return unionTypeName[i]
}
// Format implements the NodeFormatter interface.
func (node *UnionClause) Format(ctx *FmtCtx) {
ctx.FormatNode(node.Left)
ctx.WriteByte(' ')
ctx.WriteString(node.Type.String())
if node.All {
ctx.WriteString(" ALL")
}
ctx.WriteByte(' ')
ctx.FormatNode(node.Right)
}