How to Execute a SELECT Query with a NOT IN Subquery using CodeIgniter Active Record?

CodeIgniter Active Record: Executing a SELECT Query with a NOT IN Subquery

In this scenario, you want to retrieve all rows from the 'certs' table that are not present in the 'revokace' table. Conventional SQL syntax for this query would be:

SELECT *
FROM certs
WHERE id NOT IN (SELECT id_cer FROM revokace);

To achieve this using CodeIgniter's Active Record pattern, you can utilize the '->where()' method. However, it's important to handle potential conflicts with special characters in your query.

Solution:

CodeIgniter's '->where()' method conveniently supports passing custom query strings directly to the database. This allows you to write your query as:

$this->db->select('*')
         ->from('certs')
         ->where('`id` NOT IN (SELECT `id_cer` FROM `revokace`)', NULL, FALSE);

In this query, the 'NULL,FALSE' arguments ensure that CodeIgniter does not perform any escaping, preserving the integrity of your subquery.

Optional Alternative:

For further code optimization, consider using the CodeIgniter Subquery Library. It simplifies subquery creation by providing a dedicated interface. Your query using the Subquery Library would look like this:

$this->db->select('*')
         ->from('certs');

$sub = $this->subquery->start_subquery('where_in')
                       ->select('id_cer')
                       ->from('revokace');

$this->subquery->end_subquery('id', FALSE);

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