How to add data after comparison in codeigniter - php

Question

I have two tables (mark and enroll). Mark table contains two students (ally, hassan) while Enroll table contains four students (ally, hassan, zuwena, saada).
I need to compare these two tables, then after comparison to add missing students from enroll table into mark table without duplication.
But I'm using codeigniter.
I tried this but I got errors'
$data['exam_id'] = $this->input->post('exam_id');
$data['class_id'] = $this->input->post('class_id');
$data['section_id'] = $this->input->post('section_id');
$data['subject_id'] = $this->input->post('subject_id');
$data['year'] = $this->db->get_where('settings' , array('type'=>'running_year'))->row()->description;
$query = $this->db->get_where('mark' , array(
'exam_id' => $data['exam_id'],
'class_id' => $data['class_id'],
'section_id' => $data['section_id'],
'subject_id' => $data['subject_id'],
'year' => $data['year']
))->result_array();
$query1 = $this->db->get_where('enroll', array(
'class_id' => $data['class_id'],
'section_id' => $data['section_id'],
'year' => $data['year']))->result_array();
$query3 = count($query1);
$query4 = count($query);
if ($query3 != $query4){
$students = $this->db->get_where('enroll' , array(
'class_id' => $data['class_id'] , 'section_id' => $data['section_id'] , 'year' => $data['year']))->result_array();
foreach($students as $row)
{
$data['student_id'] = $row['student_id'];
$this->db->not_like('mark' , $data);
$query5 = $this->db->from('mark');
$this->db->insert('mark' , $query5);
}

Answer 1

Based on your previous codes, if you want to add the missing mark data from enroll data, you could change your foreach block to :
if ($query3 != $query4){
// first get all the mark student_id data
$mark_student_id = $this->db->select('student_id')->get('mark')->result_array();
// then filter enroll data which does not contain mark student_id data
$new_students = $this->db->where( array(
'class_id' => $data['class_id'] , 'section_id' => $data['section_id'] , 'year' => $data['year']
))->where_not_in('student_id' , array_column($mark_student_id, 'student_id'))->get('enroll')->result_array();
// then insert filtered enroll data to mark table
$this->db->insert('mark' , $new_students);
you could restore the previous codes on your question

Answer 2

Thanks #Hasta Dhana, I have done a little changes to your answer according to my needs and to solve this error "you have to use the set method to update an entry" as follows,
if ($query3 != $query4){
// first get all the mark student_id data
$this->db->where(array('exam_id' => $data['exam_id'],'subject_id' => $data['subject_id']));
$mark_student_id = $this->db->select('student_id')->get('mark')->result_array();
if(count($mark_student_id)>0){
// then filter enroll data which does not contain mark student_id data
$new_students = $this->db->where( array(
'class_id' => $data['class_id'] , 'section_id' => $data['section_id'] , 'year' => $data['year']
))->where_not_in('student_id' , array_column($mark_student_id, 'student_id'))->get('enroll');
// then insert filtered enroll data to mark table
if($new_students->num_rows()>0){
foreach ($new_students->result_array() as $row){
$data['student_id'] = $row['student_id'];
$this->db->insert('mark' , $data);
}
}
}else {
$data1['exam_id'] = $this->input->post('exam_id');
$data1['class_id'] = $this->input->post('class_id');
$data1['section_id'] = $this->input->post('section_id');
$data1['subject_id'] = $this->input->post('subject_id');
$data1['year'] = $this->db->get_where('settings' , array('type'=>'running_year'))->row()->description;
$students = $this->db->get_where('enroll' , array(
'class_id' => $data1['class_id'] , 'section_id' => $data1['section_id'] , 'year' => $data1['year']))->result_array();
foreach($students as $row)
{
$data1['student_id'] = $row['student_id'];
$this->db->insert('mark' , $data1);
}
}
}
That is how was done, thanks.