How to convert a complex select query to Drupal dynamic query?

Question

I read online that db_query is faster than db_select for complex queries. I wanted to check this for one of the queries I have written.

Following is the code with db_query:

$query = "SELECT og_users_roles.uid
        FROM {og_users_roles} AS og_users_roles
          LEFT JOIN {og_role} AS og_role
            ON og_users_roles.rid = og_role.rid
          LEFT JOIN {users} AS users
            ON og_users_roles.uid = users.uid
        WHERE og_users_roles.gid = :gid
          AND og_role.name =  :role_name
          AND users.uid <> 0
          AND users.status = 1";

$placeholders = array(
  ':gid' => $group_entity->nid,
  ':role_name' => OG_ADMINISTRATOR_ROLE,
);

$results = db_query($query, $placeholders)->fetchAll();

Now, before testing the performance I need to change above to user db_select.

This is what I have done:

$query = db_select('og_users_roles', 'o_u_r')
  ->leftJoin('og_role', 'o_r', 'o_u_r.rid = o_r.rid')
  ->leftJoin('user', 'u', 'o_u_r.uid = u.uid')
  ->fields('o_u_r', array('uid'))
  ->condition('o_u_r.gid', $group_entity->nid)
  ->condition('o_r.name', OG_ADMINISTRATOR_ROLE)
  ->condition('u.uid', 0, '<>')
  ->condition('u.status', 1);

$results = $query->execute()->fetchAll();

However, this seems to fail with a WSOD. Can someone point the error?

Answer 1

Give a try to Query coder module ( https://www.drupal.org/project/query_coder ): Convert SQL query to Drupal Database abstraction layer code.

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Otherwise to debug the error turn on the error reporting, and check the error log which will point you to the suitable path.