如何避免重复并在行已存在时选择一行？

Question

I'm trying to generate a report of all courses in all curriculum's. My problem is that if two curriculum's have the same course, the query will bring them both. What I need if the course in both curriculum, fetch one of them only.

'curriculumcourses' Table: in this table are all courses in different curriculums.

The problem happen when for example:

course_id=1
curriculum_id=1
set_numer=0 //this row is not related to the problem

course_id=1
curriculum_id=2
set_numer=0 //this row is not related to the problem

The same course_id in different curriculum which is correct, but when I need to generate this report I don't need to show both courses I need just one. any help would be highly appreciated.

Here is the query I'm using

$result2 ="SELECT 
  * 
FROM
  curriculumcourses NATURAL 
  JOIN courses 
WHERE semester_ava = '$avalablesemster' 
  AND curriculum_id IN 
  (SELECT 
    curriculum_id 
  FROM
    curriculum 
  WHERE '".$coursneededdate."'
   BETWEEN startdate  AND enddate ";
if(!empty($gradunder)){
 $result2 .=" AND grad_under = '".$gradunder."'";
}
 $result2 .=")";

Answer 1

Use GROUP BY:

$result2 ="SELECT 
  * 
FROM
  curriculumcourses NATURAL 
  JOIN courses 
WHERE semester_ava = '$avalablesemster' 
  AND curriculum_id IN 
  (SELECT 
    curriculum_id 
  FROM
    curriculum 
  WHERE '".$coursneededdate."'
   BETWEEN startdate  AND enddate ";
if(!empty($gradunder)){
 $result2 .=" AND grad_under = '".$gradunder."'";
}
 $result2 .=") GROUP BY (course_id);";