add In() function

engine.go

@@ -64,6 +64,11 @@ func (engine *Engine) Id(id int) *Engine {
 	return engine
 }
 
+func (engine *Engine) In(column string, args ...interface{}) *Engine {
+	engine.Statement.In(column, args...)
+	return engine
+}
+
 func (engine *Engine) Limit(limit int, start ...int) *Engine {
 	engine.Statement.Limit(limit, start...)
 	return engine

session.go

@@ -37,6 +37,11 @@ func (session *Session) Id(id int) *Session {
 	return session
 }
 
+func (session *Session) In(column string, args ...interface{}) *Session {
+	session.Statement.In(column, args...)
+	return session
+}
+
 func (session *Session) Limit(limit int, start ...int) *Session {
 	session.Statement.Limit(limit, start...)
 	return session

statement.go

@@ -2,6 +2,7 @@ package xorm
 
 import (
 	"fmt"
+	"strings"
 )
 
 type Statement struct {
@@ -19,6 +20,14 @@ type Statement struct {
 	BeanArgs   []interface{}
 }
 
+func MakeArray(elem string, count int) []string {
+	res := make([]string, count)
+	for i := 0; i < count; i++ {
+		res[i] = elem
+	}
+	return res
+}
+
 func (statement *Statement) Init() {
 	statement.Table = nil
 	statement.Start = 0
@@ -48,6 +57,17 @@ func (statement *Statement) Id(id int) {
 	}
 }
 
+func (statement *Statement) In(column string, args ...interface{}) {
+	inStr := fmt.Sprintf("%v in (%v)", column, strings.Join(MakeArray("?", len(args)), ","))
+	if statement.WhereStr == "" {
+		statement.WhereStr = inStr
+		statement.Params = args
+	} else {
+		statement.WhereStr = statement.WhereStr + " and " + inStr
+		statement.Params = append(statement.Params, args...)
+	}
+}
+
 func (statement *Statement) Limit(limit int, start ...int) {
 	statement.LimitN = limit
 	if len(start) > 0 {

xorm_test.go

@@ -190,6 +190,23 @@ func where(t *testing.T) {
 	fmt.Println(users)
 }
 
+func in(t *testing.T) {
+	users := make([]Userinfo, 0)
+	err := engine.In("id", 1, 2, 3).Find(&users)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	fmt.Println(users)
+
+	err = engine.Where("id > ?", 2).In("id", 1, 2, 3).Find(&users)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	fmt.Println(users)
+}
+
 func limit(t *testing.T) {
 	users := make([]Userinfo, 0)
 	err := engine.Limit(2, 1).Find(&users)
@@ -341,6 +358,7 @@ func TestMysql(t *testing.T) {
 	find(t)
 	count(t)
 	where(t)
+	in(t)
 	limit(t)
 	order(t)
 	join(t)
@@ -366,6 +384,7 @@ func TestSqlite(t *testing.T) {
 	find(t)
 	count(t)
 	where(t)
+	in(t)
 	limit(t)
 	order(t)
 	join(t)