WIP feature replacement

builder.go

@@ -12,12 +12,13 @@ import (
 type optype byte
 
 const (
-	condType   optype = iota // only conditions
-	selectType               // select
-	insertType               // insert
-	updateType               // update
-	deleteType               // delete
-	unionType                // union
+	condType    optype = iota // only conditions
+	selectType                // select
+	insertType                // insert
+	updateType                // update
+	deleteType                // delete
+	unionType                 // union
+	replaceType               // replace
 )
 
 const (
@@ -47,20 +48,21 @@ type limit struct {
 // Builder describes a SQL statement
 type Builder struct {
 	optype
-	dialect    string
-	isNested   bool
-	tableName  string
-	subQuery   *Builder
-	cond       Cond
-	selects    []string
-	joins      []join
-	unions     []union
-	limitation *limit
-	inserts    Eq
-	updates    []Eq
-	orderBy    string
-	groupBy    string
-	having     string
+	dialect      string
+	isNested     bool
+	tableName    string
+	subQuery     *Builder
+	cond         Cond
+	selects      []string
+	joins        []join
+	unions       []union
+	limitation   *limit
+	inserts      Eq
+	updates      []Eq
+	replacements []interface{}
+	orderBy      string
+	groupBy      string
+	having       string
 }
 
 // Dialect sets the db dialect of Builder.
@@ -131,6 +133,14 @@ func (b *Builder) TableName() string {
 	return b.tableName
 }
 
+// Replace replace SQL
+func (b *Builder) Replace(replacements ...interface{}) *Builder {
+	b.replacements = replacements
+	b.optype = replaceType
+
+	return b
+}
+
 // Into sets insert table name
 func (b *Builder) Into(tableName string) *Builder {
 	b.tableName = tableName
@@ -278,6 +288,8 @@ func (b *Builder) WriteTo(w Writer) error {
 		return b.deleteWriteTo(w)
 	case unionType:
 		return b.unionWriteTo(w)
+	case replaceType:
+		return b.replaceWriteTo(w)
 	}
 
 	return ErrNotSupportType

builder_replace.go

@@ -0,0 +1,80 @@
+// 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) replaceWriteTo(w Writer) error {
+	if len(b.tableName) == 0 {
+		return ErrNoTableName
+	}
+
+	if len(b.replacements) == 0 && b.subQuery == nil {
+		return fmt.Errorf("empty replacements")
+	}
+
+	var cols []string
+	var conditions []Eq
+	if len(b.replacements) > 0 {
+		switch b.replacements[0].(type) {
+		case string:
+			cols = make([]string, 0, len(b.replacements))
+			for e := range b.replacements {
+				if val, ok := b.replacements[e].(string); ok {
+					cols = append(cols, val)
+				} else {
+					return fmt.Errorf("non-uniform types")
+				}
+			}
+
+			if b.subQuery == nil {
+				return fmt.Errorf("derived table should not be empty")
+			}
+		case Eq:
+			conditions = make([]Eq, 0, len(b.replacements))
+			for e := range b.replacements {
+				if val, ok := b.replacements[e].(Eq); ok {
+					conditions = append(conditions, val)
+				} else {
+					return fmt.Errorf("non-uniform types in replacements")
+				}
+			}
+		default:
+			return fmt.Errorf("unsupported replacement type, supposed to be string or Eq cond")
+		}
+	}
+
+	switch b.dialect {
+	case MYSQL:
+		if len(conditions) > 0 {
+			fmt.Fprintf(w, "REPLACE INTO %v SET ", b.tableName)
+
+			for e := range conditions {
+				if err := conditions[e].WriteTo(w); err != nil {
+					return err
+				}
+
+				if e != len(conditions)-1 {
+					fmt.Fprintf(w, ",")
+				}
+			}
+		} else {
+			if len(cols) == 0 {
+				fmt.Fprintf(w, "REPLACE INTO %v ", b.tableName)
+			} else {
+				fmt.Fprintf(w, "REPLACE INTO %v(%v) ", b.tableName, strings.Join(cols, ","))
+			}
+
+			return b.subQuery.WriteTo(w)
+		}
+	default:
+		return ErrNotSupportType
+	}
+
+	return nil
+}

builder_replace_test.go

@@ -0,0 +1,32 @@
+// 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 (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuilder_Replace(t *testing.T) {
+	sql, err := MySQL().Replace(Eq{"a": 1}, Eq{"b": 2}, Eq{"c": "3"}).Into("table1").ToBoundSQL()
+	assert.NoError(t, err)
+	assert.EqualValues(t, "REPLACE INTO table1 SET a=1,b=2,c='3'", sql)
+
+	sql, err = MySQL().Replace().Into("table1").From(
+		Select("a", "b", "c").From("table2")).ToBoundSQL()
+	assert.NoError(t, err)
+	assert.EqualValues(t, "REPLACE INTO table1 SELECT a,b,c FROM table2", sql)
+
+	sql, err = MySQL().Replace("a", "b", "c").Into("table1").From(
+		Select("a", "b", "c").From("table2")).ToBoundSQL()
+	assert.NoError(t, err)
+	assert.EqualValues(t, "REPLACE INTO table1(a,b,c) SELECT a,b,c FROM table2", sql)
+
+	sql, err = MySQL().Replace("a", "b", "c").Into("table1").From(
+		Select("a", "b", "c").From("table2").Where(Neq{"a": 1})).ToBoundSQL()
+	assert.NoError(t, err)
+	assert.EqualValues(t, "REPLACE INTO table1(a,b,c) SELECT a,b,c FROM table2 WHERE a<>1", sql)
+}