[php] CodeIgniter Select Query

I have a simple CodeIgniter Active record query to select an ID:

$q = $this -> db
           -> select('id')
           -> where('email', $email)
           -> limit(1)
           -> get('users');

How can I assign the above ID to a variable (eg. $id) For example,

echo "ID is" . $id;

Thanks.

public function getSalary()
    {
        $this->db->select('tbl_salary.*,tbl_employee.empFirstName');
        $this->db->from('tbl_salary');
        $this->db->join('tbl_employee','tbl_employee.empID = strong texttbl_salary.salEmpID');
        $this->db->where('tbl_salary.status',0);
        $query = $this->db->get();
        return $query->result();
    }

use Result Rows.
row() method returns a single result row.

$id = $this 
    -> db
    -> select('id')
    -> where('email', $email)
    -> limit(1)
    -> get('users')
    -> row();

then, you can simply use as you want. :)

echo "ID is" . $id;

$query= $this->m_general->get('users' , array('id'=> $id ));
echo $query[''];

is ok ;)

This is your code

$q = $this -> db
       -> select('id')
       -> where('email', $email)
       -> limit(1)
       -> get('users');

Try this

$id = $q->result()[0]->id;

or this one, it's simpler

$id = $q->row()->id;

Here is the example of the code:

public function getItemName()
{
    $this->db->select('Id,Name');
    $this->db->from('item');
    $this->db->where(array('Active' => 1));
    return $this->db->get()->result();
}

function news_get_by_id ( $news_id )
{

    $this->db->select('*');
    $this->db->select("DATE_FORMAT( date, '%d.%m.%Y' ) as date_human",  FALSE );
    $this->db->select("DATE_FORMAT( date, '%H:%i') as time_human",      FALSE );


    $this->db->from('news');

    $this->db->where('news_id', $news_id );


    $query = $this->db->get();

    if ( $query->num_rows() > 0 )
    {
        $row = $query->row_array();
        return $row;
    }

}   
This 

echo $this->db->select('title, content, date')->get_compiled_select();

one short way would be

$id = $this -> db
       -> select('id')
       -> where('email', $email)
       -> limit(1)
       -> get('users')
       -> row()
       ->id;
echo "ID is ".$id;

When use codeIgniter Framework then refer this active records link. how the data interact with structure and more.

The following functions allow you to build SQL SELECT statements.

Selecting Data

$this->db->get();

Runs the selection query and returns the result. Can be used by itself to retrieve all records from a table:

$query = $this->db->get('mytable');

With access to each row

$query = $this->db->get('mytable');

foreach ($query->result() as $row)
{
    echo $row->title;
}

Where clues

$this->db->get_where();

EG:

 $query = $this->db->get_where('mytable', array('id' => $id), $limit, $offset);

Select field

$this->db->select('title, content, date');

$query = $this->db->get('mytable');

// Produces: SELECT title, content, date FROM mytable

E.G

$this->db->select('(SELECT SUM(payments.amount) FROM payments WHERE payments.invoice_id=4') AS amount_paid', FALSE); 
$query = $this->db->get('mytable');