select * from class c,teacher t where c.teacher_id=t.t_id and c.c_id=#{id}  
    
    
      
      
      
        
        
      
    

  
      
      
      
      
      
    
    
    
    SELECT  
      t.id,  
      t.NAME,  
      t.class_name  
    FROM  
      teacher t  
    
    
    select   
      s.id,  
      s. NAME,  
      s.class_name as className  
    from student s  
    where teacher_id = #{id}  
   

  
  select cid,cname from country where cid=#{ooo}  
  
  
    
    
    
  
    
  select pid,pname,countryId from people where pid = #{xxx}