forkjo/vendor/github.com/go-xorm/builder/builder_union.go

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// Copyright 2018 The Xorm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package builder
import (
"fmt"
"strings"
)
func (b *Builder) unionWriteTo(w Writer) error {
if b.limitation != nil || b.cond.IsValid() ||
b.orderBy != "" || b.having != "" || b.groupBy != "" {
return ErrNotUnexpectedUnionConditions
}
for idx, u := range b.unions {
current := u.builder
if current.optype != selectType {
return ErrUnsupportedUnionMembers
}
if len(b.unions) == 1 {
if err := current.selectWriteTo(w); err != nil {
return err
}
} else {
if b.dialect != "" && b.dialect != current.dialect {
return ErrInconsistentDialect
}
if idx != 0 {
fmt.Fprint(w, fmt.Sprintf(" UNION %v ", strings.ToUpper(u.unionType)))
}
fmt.Fprint(w, "(")
if err := current.selectWriteTo(w); err != nil {
return err
}
fmt.Fprint(w, ")")
}
}
return nil
}