170 lines
3.4 KiB
Go
170 lines
3.4 KiB
Go
// Copyright 2016 The Xorm Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package builder
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import (
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"fmt"
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)
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// Select creates a select Builder
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func Select(cols ...string) *Builder {
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builder := &Builder{cond: NewCond()}
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return builder.Select(cols...)
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}
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func (b *Builder) selectWriteTo(w Writer) error {
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if len(b.from) <= 0 && !b.isNested {
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return ErrNoTableName
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}
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// perform limit before writing to writer when b.dialect between ORACLE and MSSQL
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// this avoid a duplicate writing problem in simple limit query
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if b.limitation != nil && (b.dialect == ORACLE || b.dialect == MSSQL) {
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return b.limitWriteTo(w)
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}
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if _, err := fmt.Fprint(w, "SELECT "); err != nil {
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return err
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}
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if len(b.selects) > 0 {
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for i, s := range b.selects {
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if _, err := fmt.Fprint(w, s); err != nil {
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return err
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}
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if i != len(b.selects)-1 {
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if _, err := fmt.Fprint(w, ","); err != nil {
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return err
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}
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}
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}
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} else {
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if _, err := fmt.Fprint(w, "*"); err != nil {
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return err
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}
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}
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if b.subQuery == nil {
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if _, err := fmt.Fprint(w, " FROM ", b.from); err != nil {
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return err
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}
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} else {
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if b.cond.IsValid() && len(b.from) <= 0 {
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return ErrUnnamedDerivedTable
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}
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if b.subQuery.dialect != "" && b.dialect != b.subQuery.dialect {
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return ErrInconsistentDialect
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}
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// dialect of sub-query will inherit from the main one (if not set up)
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if b.dialect != "" && b.subQuery.dialect == "" {
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b.subQuery.dialect = b.dialect
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}
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switch b.subQuery.optype {
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case selectType, setOpType:
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fmt.Fprint(w, " FROM (")
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if err := b.subQuery.WriteTo(w); err != nil {
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return err
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}
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if len(b.from) == 0 {
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fmt.Fprintf(w, ")")
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} else {
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fmt.Fprintf(w, ") %v", b.from)
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}
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default:
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return ErrUnexpectedSubQuery
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}
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}
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if err := b.joins.WriteTo(w); err != nil {
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return err
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}
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if b.cond.IsValid() {
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if _, err := fmt.Fprint(w, " WHERE "); err != nil {
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return err
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}
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if err := b.cond.WriteTo(w); err != nil {
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return err
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}
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}
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if len(b.groupBy) > 0 {
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if _, err := fmt.Fprint(w, " GROUP BY ", b.groupBy); err != nil {
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return err
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}
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}
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if b.having != nil {
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switch c := b.having.(type) {
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case string:
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if len(c) > 0 {
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if _, err := fmt.Fprint(w, " HAVING ", c); err != nil {
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return err
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}
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}
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case Cond:
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if c.IsValid() {
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if _, err := fmt.Fprint(w, " HAVING "); err != nil {
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return err
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}
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if err := c.WriteTo(w); err != nil {
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return err
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}
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}
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default:
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return fmt.Errorf("unknown having parameter: %#v", b.having)
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}
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}
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if b.orderBy != nil {
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switch c := b.orderBy.(type) {
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case string:
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if len(c) > 0 {
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if _, err := fmt.Fprint(w, " ORDER BY ", c); err != nil {
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return err
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}
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}
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case *Expression:
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if _, err := fmt.Fprint(w, " ORDER BY "); err != nil {
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return err
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}
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if err := c.WriteTo(w); err != nil {
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return err
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}
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default:
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return fmt.Errorf("unknow orderby parameter: %#v", b.orderBy)
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}
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}
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if b.limitation != nil {
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if err := b.limitWriteTo(w); err != nil {
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return err
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}
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}
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return nil
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}
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// OrderBy orderBy SQL
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func (b *Builder) OrderBy(orderBy interface{}) *Builder {
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b.orderBy = orderBy
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return b
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}
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// GroupBy groupby SQL
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func (b *Builder) GroupBy(groupby string) *Builder {
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b.groupBy = groupby
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return b
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}
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// Having having SQL
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func (b *Builder) Having(having interface{}) *Builder {
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b.having = having
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return b
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}
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