yii 常用的多表查询

1         return $this->model()->getDbConnection()->createCommand()
2                    ->select("t.type,t.title,t.class_id,t.thumb,t.hours,t.real_price,t.price,c.name,p.cert_id")
3                    ->leftjoin(ClassroomClass::model()->tableName() .' c'," t.class_id = c.id")
4                    ->leftjoin(ClassroomProductCert::model()->tableName() .' p'," t.id = p.product_id")
5                    ->from($this->tableName() .' t')
6                    ->where("t.id = $course_id")
7                    ->queryRow();

第二种：

 1    $criteria =newCDbCriteria; 
 2 
 3 
 4    $criteria->addCondition("id=1"); //查询条件，即where id =1  
 5    $criteria->addInCondition('id', array(1,2,3,4,5));//代表where id IN (1,23,,4,5,);  
 6    $criteria->addNotInCondition('id',array(1,2,3,4,5));//与上面正好相法，是NOT IN  
 7    $criteria->addCondition('id=1','OR');//这是OR条件，多个条件的时候，该条件是OR而非AND 
 8    $criteria->addSearchCondition('name','分类');//搜索条件，其实代表了。。where name like '%分类%'  
 9    $criteria->addBetweenCondition('id', 1, 4);//between1 and 4   
10      
11    $criteria->compare('id',1);   //这个方法比较特殊，他会根据你的参数自动处理成addCondition或者addInCondition， 
12                                    //即如果第二个参数是数组就会调用addInCondition  
13     
14    $criteria->addCondition("id = :id"); 
15    $criteria->params[':id']=1;  
16     
17    $criteria->select = 'id,parentid,name';//代表了要查询的字段，默认select='*';  
18    $criteria->join = 'xxx'; //连接表 
19    $criteria->with = 'xxx';//调用relations   
20    $criteria->limit =10;   //取1条数据，如果小于0，则不作处理  
21    $criteria->offset =1;   //两条合并起来，则表示 limit 10 offset1,或者代表了。limit 1,10  
22    $criteria->order = 'xxx DESC,XXX ASC' ;//排序条件 
23    $criteria->group = 'group 条件'; 
24    $criteria->having = 'having 条件 '; 
25    $criteria->distinct = FALSE;//是否唯一查询