Question

Can I pull out data by using variable in SQL?

For example,

In controller

$frontbottom = $this->MProducts -> getFeatureProducts('Front bottom');

In model

//This does not work.
  function getFeatureProducts($catname){
     $data = array();
     $Q = $this->db->query('SELECT P.*, C.Name AS CatName 
                   FROM omc_products AS P
                   LEFT JOIN omc_categories AS C
                   ON C.id = P.category_id
                   WHERE C.Name = $catname
                   AND p.status = "active"
                   ORDER BY RAND()
                   ');
     if ($Q->num_rows() > 0){
       foreach ($Q->result_array() as $row){
         $data[] = $row;
       }
    }
    $Q->free_result();    
    return $data;  

 }

This does not work. Is it because I am using variable?

The following works.
In controller

$frontbottom = $this->MProducts -> getFrontbottom();

In model

function getFrontbottom(){
     $data = array();

     $Q = $this->db->query('SELECT P.*, C.Name AS CatName 
                   FROM omc_products AS P
                   LEFT JOIN omc_categories AS C
                   ON C.id = P.category_id
                   WHERE C.Name = "Front bottom"
                   AND p.status = "active"
                   ORDER BY RAND()
                   ');
     if ($Q->num_rows() > 0){
       foreach ($Q->result_array() as $row){
         $data[] = $row;
       }
    }
    $Q->free_result();    
    return $data;  

 }

Can I use variable in SQL?

If not, what is the best way? Do I have make same SQL again and again just changing WHERE clause?

Answer 1

For one thing, your quotes are mixed up. If you want to include a variable in a string, you need to use double quotes rather than single quotes. Also, the quotes around “active” should be single quotes. Try this and I think it should work:

$this->db->query("SELECT P.*, C.Name AS CatName 
                   FROM omc_products AS P
                   LEFT JOIN omc_categories AS C
                   ON C.id = P.category_id
                   WHERE C.Name = '$catname'
                   AND p.status = 'active'
                   ORDER BY RAND()
                   ");