Question

I wanted to know how to check whether there is a value present in a table (managers) and then add a ‘yes’ or ‘no’ string depending on if there is a value in that table or not.

$this->db->select('employees.first_name, employees.last_name, departments.department_name, departments.department_numb, titles.title');
            $this->db->from('employees');
            $this->db->where('first_name', $firstname);
            $this->db->where('last_name', $lastname);
            $this->db->join('department_manager', 'department_manager.emp_numb = employees.emp_numb', 'inner');
            $this->db->join('departments', 'departments.department_numb = department_manager.department_numb', 'inner');
            $this->db->join('titles', 'titles.emp_numb = employees.emp_numb', 'inner');
            $this->db->where('department_name', $dept);
            $this->db->where('title', $jobtitle);
            $result = $this->db->get();

            $data = array();
            foreach($result->result() as $row)
            {
                $entry = array();
                $entry['firstname'] = $row->first_name;
                $entry['lastname'] = $row->last_name;
                $entry['jobtitle'] = $row->title;
                $entry['dept'] = $row->department_name;
                $entry['deptid'] = $row->department_number;
                //$entry['ismanager'] = 

                $data[] = $entry;
            }
            return $data;

I want to check whether an employee is present in the table 'department_manager' which is joined by an employees number. So if that employee number is not present in the table ‘department_manager’ then I want to insert in the array index $entry[ismanager'] a string which says ‘no’, and if the employee number is present in the table ‘department_manager’ then I want $entry['ismanager'] to hold the string ‘yes’.

But I’m confused as to how to check that the employee is present or not in that table. Do I do it in the active record query or in the foreach loop? And if it is done in the foreach loop then how do I make that comparison as the query is completed?

Answer 1

Why have a field that is basically a calculated value? That’s like having fields for quantity per box, quantity of boxes then saving the total items to a third field. Never save to the database something you can gain access to via a quick query. In your query above it’s as simple as changing the dept manager join to a left join, including the dept manager id and saying if that field is blank in a record the person is not a manager. Using a LEFT join will return all records whether they have an entry in the management table or not.

Add: department_manager.emp_numb to the select.

The Join:

$this->db->join('department_manager', 'department_manager.emp_numb
= employees.emp_numb', 'left');

Then in the foreach:

if(!$row->department_manager.emp_numb)
 {
    this person is not a manager;
 } 

If you feel you really must have that extra field then you can still populate it with the method above.