php - how to calculate the sum of grades for each student -


i have 1 table grades of exams, , students (the students table have 10 students only).

i want output array in json format students details sum of grades of each semester in array of array.

expected output

[     {     "id": "1", -> semester id     "student1": {"id": "1","name": "student name", "bio": "50", "chem": "50", "math": "60", "total grades": "160"},     "student2": {"id": "2","name": "secondstudent name", "bio": "60", "chem": "60", "math": "50", "total grades": "170"},     } ]

here tables structure

tbstudents

   id   ,    name                     1   ,    student name             2   ,    secondstudent name      3   ,    thirdstudent name

tbgrades

    id   ,  student   ,  semster    ,   bio    ,   chem    ,   math   ,  total      1   ,     1      ,     1       ,   50     ,    50     ,   60     ,   160      2   ,     2      ,     1       ,   30     ,    40     ,   20     ,   90      3   ,     2      ,     1       ,   30     ,    20     ,   30     ,   80

challenge

how calculate sum of each bio, chem, math, total each student semester, cause student might have multiple grades in same semester

what i've tried

$sql = "select grade.id g_id, grade.semester g_semester, grade.bio g_bio, grade.chem g_chem, grade.math g_math, grade.total g_total, student.id s_id, student.name s_name tbgrades grade inner join tbstudents student on student.id = grade.student";  try {     $db = new db();     $db = $db->connect();     $stmt = $db->prepare($sql);      $stmt->execute();      $grade = $stmt->fetchall(pdo::fetch_obj);      $db = null;      if(empty($grade)) {         $response->getbody()->write         ('         {             "error":             {                 "status":"400",                 "message":"invalid request"             }         }');     } else {          foreach($grade $value) {             $array_resp[]=[                 'id' => $value->g_id,                 'student1' => ['id'=>$value->s_id, 'name'=>$value->s_name, 'bio'=>$value->g_bio, 'chem'=>$value->g_chem, 'math'=>$value->g_math, 'total grades'=>$value->g_total],              ];         }         $response->getbody()->write(json_encode($array_resp));     } } catch(pdoexception $e) {     $response->getbody()->write     ('     {         "error":         {             "message":'. $e->getmessage() .'         }     }'); }

you can using mysql group by clause. 

select  grade.id g_id,  grade.semester g_semester,  sum(grade.bio) g_bio,  sum(grade.chem) g_chem,  sum(grade.math) g_math,  sum(grade.total) g_total,  student.id s_id,  student.name s_name  tbgrades grade  inner join  tbstudents student  on  student.id = grade.student group student.id,  grade.semester

Comments

Post a Comment

Popular posts from this blog

python - Operations inside variables -

this question has answer here: evaluating mathematical expression in string 12 answers i want make python script finds maximum possible output using 2 operations. problem says there syntax error @ 2nd last line, in b in there. how can fix it? x = 0 = int(input("1st number:")) c = int(input("2nd number:" )) e = int(input("3rd number:" )) in range(4): if == 0: b = "+" elif == 1: b = "-" elif == 2: b = "/" else: b = "*" j in range(4): if j == 0: d = "+" elif j == 1: d = "-" elif j == 2: d = "/" else: d = "*" k = b c d e print(k) if you're after variables e on single line, couldn...
Read more

Generic Map Parameter java -

i having lot of methods of type: public static list<eduusers> getdetails(class c, map<string, integer> params) { list<eduusers> details = null; session session = hibernateutil.getsessionfactory().opensession(); transaction tx = null; try { tx = session.begintransaction(); criteria cr = session.createcriteria(c); (map.entry<string, integer> entry : params.entryset()) { cr.add(restrictions.eq(entry.getkey(), entry.getvalue())); } details = cr.list(); tx.commit(); } catch (exception asd) { log.debug(asd.getmessage()); if (tx != null) { tx.commit(); } } { session.close(); } return details; } i trying have generic method them , have written far: public static <t> list<t> getdetails(class<t> c, class<t> b) { l...
Read more

arrays - What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it? -

what arrayindexoutofboundsexception mean , how rid of it? here code sample triggers exception: string[] name = {"tom", "dick", "harry"}; for(int = 0; i<=name.length; i++) { system.out.print(name[i] +'\n'); } your first port of call should documentation explains reasonably clearly: thrown indicate array has been accessed illegal index. index either negative or greater or equal size of array. so example: int[] array = new int[5]; int boom = array[10]; // throws exception as how avoid it... um, don't that. careful array indexes. one problem people run thinking arrays 1-indexed, e.g. int[] array = new int[5]; // ... populate array here ... (int index = 1; index <= array.length; index++) { system.out.println(array[index]); } that miss out first element (index 0) , throw exception when index 5. valid indexes here 0-4 inclusive. correct, idiomatic for statement here be: for (int index = 0; index <...
Read more