=======================================

    public function getMinLimit () {
        $sql = "...";
        $result = yii::app()->db->createCommand($sql);
        $query = $result->queryAll();
        return array (
                $query [0] [‘max‘],
        );
    }

$connection=Yii::app()->db;
$sql="SELECT u.account,i.* FROM sys_user as u left join user_info as i on u.id=i.user_id";
$rows=$connection->createCommand($sql)->query();
foreach ($rows as $k => $v ){
    echo $v[‘add_time‘];
}

======================================== 事务

$db = Yii::app()->db;
$dbTrans = $db->beginTransaction();

$dbTrans->commit();
$dbTrans->rollback();

========================================  分页

一般写法：
$criteria = new CDbCriteria;
$count = DnOnline::model()->count($criteria);
$pages = new CPagination($count);              
$pages->pageSize = 5;
$pages->applylimit($criteria);
$model = DnOnline::model()->findAll($criteria);

记得控制器里有个函数paginate($itemCount,$pageSize=null,$pageVar=null)
CDB写法：

$criteria = new CDbCriteria;
$sql = "SELECT * FROM USER";
$model= Yii::app()->db->createCommand($sql)->queryAll();
$pages = new CPagination(count($model));              
$pages->pageSize = 4;
$pages->applylimit($criteria);
$model=Yii::app()->db->createCommand($sql." LIMIT :offset,:limit");
$model->bindValue(‘:offset‘, $pages->currentPage*$pages->pageSize);
$model->bindValue(‘:limit‘, $pages->pageSize);
$model=$model->queryAll();



或者:

      $criteria = new CDbCriteria;
      $connection=Yii::app()->db;
      $sql="SELECT u.account,i.* FROM sys_user as u left join user_info as i on u.id=i.user_id ";
      $model= Yii::app()->db->createCommand($sql)->queryAll();
      $pages = new CPagination(count($model));              
      $pages->pageSize = 4;
      $pages->applylimit($criteria);

      $model=Yii::app()->db->createCommand($sql." LIMIT :offset,:limit");
      $model->bindValue(‘:offset‘, $pages->currentPage*$pages->pageSize);
      $model->bindValue(‘:limit‘, $pages->pageSize);
      $model=$model->queryAll();

======================================== 一、查询数据集合

1、$admin=Admin::model()->findAll($condition,$params);
该方法是根据一个条件查询一个集合，如： 
findAll("username=:name",array(":name"=>$username));    

2、$admin=Admin::model()->findAllByPk($postIDs,$condition,$params);
findAllByPk($id,"name like ‘:name‘ and age=:age",array(‘:name‘=>$name,‘age‘=>$age));   
该方法是根据主键查询一个集合，可以使用多个主键,如： 
findAllByPk(array(1,2));   

3、$admin=Admin::model()->findAllByAttributes($attributes,$condition,$params);
该方法是根据条件查询一个集合，可以是多个条件，把条件放到数组里面，如： 
findAllByAttributes(array(‘username‘=>‘admin‘));

4、$admin=Admin::model()->findAllBySql($sql,$params);
该方法是根据SQL语句查询一个数组,如：
findAllBySql("select *from admin whereusername=:name",array(‘:name‘=>‘admin‘));

========================================  二、查询对像的方法 

1、$admin=Admin::model()->findByPk($postID,$condition,$params);
 根据主键查询出一个对象,如：findByPk(1); 

 2、$row=Admin::model()->find($condition,$params);
 根据一个条件查询出一组数据，可能是多个，但是他只返回第一行数据,如：
find(‘username=:name‘,array(‘:name‘=>‘admin‘));

      $userinfo=Userinfo::model()->find(array(‘condition‘=>‘user_id=:user_id‘,‘params‘=>array(‘:user_id‘=>$uid)));
      print_r($userinfo->user_id);

 3、$admin=Admin::model()->findByAttributes($attributes,$condition,$params);
 该方法是根据条件查询一组数据，可以是多个条件，把条件放到数组里面，他查询的也是第一条数据，如：
findByAttributes(array(‘username‘=>‘admin‘));

 4、$admin=Admin::model()->findBySql($sql,$params);
 该方法是根据SQL语句查询一组数据,他查询的也是第一条数据，如： 
findBySql("select *from admin whereusername=:name",array(‘:name‘=>‘admin‘));

 5、拼一个获得SQL的方法，在根据find查询出一个对象 

$criteria=new CDbCriteria; 
$criteria->select=‘username‘; // only select the ‘title‘ column 
$criteria->condition=‘username=:username‘;
$criteria->params=array(‘:username=>‘admin‘);
$post=Post::model()->find($criteria); // $params isnot needed 
 
========================================  三、查询个数，判断查询是否有结果 

1、$n=Post::model()->count($condition,$params);
 该方法是根据一个条件查询一个集合有多少条记录，返回一个int型数字,如 
count("username=:name",array(":name"=>$username));   

 2、$n=Post::model()->countBySql($sql,$params);
 该方法是根据SQL语句查询一个集合有多少条记录，返回一个int型数字,如
countBySql("select *from admin whereusername=:name",array(‘:name‘=>‘admin‘));

 3、$exists=Post::model()->exists($condition,$params);
 该方法是根据一个条件查询查询得到的数组有没有数据，如果有数据返回一个true，否则没有找到

        $sql = "select count(*) as count  from " . $this->tableName() . " where user_id = $userId";
        $query = $result->queryAll();
        $pageSize =10;
        $count = $query [0] [‘count‘];
        $pageCount = ceil($count / $pageSize);
        return $pageCount;

======================================== 四、添加的方法 
$admin=newAdmin;       
$admin->username=$username;
$admin->password=$password;
if($admin->save()>0){
   echo "添加成功"; 
}else{ 
   echo "添加失败"; 
}

$userLimit = new UserLimit();
$userLimit->item = 0.30000;
if($userLimit->insert(){

}

======================================== 五、修改的方法 

$userLimitRet = UserLimit::model()->findByPk(array (
                                ‘user_id‘ => $userId,
                                ‘category_id‘ => $v
                        ));
$userLimitRet->order = $order;

if (! $userLimitRet->update()) {
}

$userAmount=userAmount::model()->findByPk($userId);
$userAmount->credit=Yii::app()->request->getParam(‘credit‘,10000);
$ret = $userAmount->save();

1、Post::model()->updateAll($attributes,$condition,$params);
 $count =Admin::model()->updateAll(array(‘username‘=>‘11111‘,‘password‘=>‘11111‘),‘password=:pass‘,array(‘:pass‘=>‘1111a1‘));
if($count>0){ 
   echo "修改成功"; 
}else{ 
   echo "修改失败"; 
} 

$ret = $this->updateAll(array (
                                ‘set‘ => $Set
                        ), " user_id in ( " . $userIds . " ) and category_id = " . $categoryId);

if($ret){
    return true;
}else {
    return false;
}

 2、Post::model()->updateByPk($pk,$attributes,$condition,$params);
 $count =Admin::model()->updateByPk(1,array(‘username‘=>‘admin‘,‘password‘=>‘admin‘));
$count =Admin::model()->updateByPk(array(1,2),array(‘username‘=>‘admin‘,‘password‘=>‘admin‘),‘username=:name‘,array(‘:name‘=>‘admin‘));
if($count>0){ 
   echo "修改成功"; 
}else{ 
   echo "修改失败"; 
} 
$pk代表主键，可以是一个也可以是一个集合，$attributes代表是要修改的字段的集合，$condition代表条件，$params传入的值

 3、Post::model()->updateCounters($counters,$condition,$params);
 $count=Admin::model()->updateCounters(array(‘status‘=>1),‘username=:name‘,array(‘:name‘=>‘admin‘));
if($count>0){ 
   echo "修改成功"; 
}else{ 
   echo "修改失败"; 
} 
array(‘status‘=>1)代表数据库中的admin表根据条件username=‘admin‘，查询出的所有结果status字段都自加1
 
======================================== 六、删除的方法 
1、Post::model()->deleteAll($condition,$params);
 $count = Admin::model()->deleteAll(‘username=:nameandpassword=:pass‘,array(‘:name‘=>‘admin‘,‘:pass‘=>‘admin‘));
         $id=1,2,3 
         deleteAll(‘id in(".$id.")‘);删除id为这些的数据
if($count>0){ 
   echo "删除成功"; 
}else{ 
   echo "删除失败"; 
} 
 2、Post::model()->deleteByPk($pk,$condition,$params);
$count = Admin::model()->deleteByPk(1);
$count =Admin::model()->deleteByPk(array(1,2),‘username=:name‘,array(‘:name‘=>‘admin‘));
if($count>0){ 
   echo "删除成功"; 
}else{ 
   echo "删除失败"; 
}