php - Retrieve a similar query -

in nutshell, page populates course, , @ bottom have 3 boxes similar courses, , similar course cannot current course refered id. similar in terms of course_title.

below how current course populated:

  $get_crs_similar = "select * courses course_id='$course_id'"; 

i retrieve 3 similar course, thinking retrieve last similar course first 1, , second last similar course, , third similar course, 3 cannot equal current course.

any appreciated.

html similar courses

        <div class="well-none">              <div id="mycarousel" class="carousel slide">                  <div class="carousel-inner">                      <div class="item active">                            <div class="row">                           <h4>  <?php echo $crs_title2; ?></h4>                             <div class="col-sm-3 col-xs-6"><a href="coursepage.php?crs_id=4656" class="thumbnail"><img src="content/negotiation.png" alt="image" width="250" height="250" class="img-responsive"></a>                             </div>                                                         <div class="col-sm-3 col-xs-6"><a href="#x" class="thumbnail"><img src="content/azure2.png" alt="image" class="img-responsive"></a>                             </div>                             <div class="col-sm-3 col-xs-6"><a href="#x" class="thumbnail"><img src="content/server.png"  alt="image" class="img-responsive"></a>                             </div>                             <div class="col-sm-3 col-xs-6"><a href="#x" class="thumbnail"><img src="content/azure3.png"  alt="image" class="img-responsive"></a>                             </div>                         </div>                     </div>                  </div>         </div>         </div>     </div> </div> </div> </div> 

use self-join:

select c1.* courses c1 join courses c2 on c1.course_title = c2.course_title , c1.course_id != c2.course_id c2.course_id = $course_id limit 3 

this return 3 courses have same title given course, not same course.