NULL compare using CodeIgniter ActiveRecord [duplicate]

Question

I've got a table like this.

[id]     [name]     [age]
1        foo        20
2        bar        NULL

If i need to return all the rows when age's fields is NULL i do the following and it works fine.

$this->db->from('person')->where('age', null);

The problem is that i need to do the opposite, i mean, return all rows when the age fields are not null values.
In SQL i do something like this

SELECT * FROM person WHERE age is not null

How do i do this using CodeIgniter ActiveRecord ??

Any help appreciated.

Answer 1

You may use:

$this->db->from('person')->where('age is not null');

If you curious how this happens see system/database/DB_active_rec.php

protected function _where($key, $value = NULL, $type = 'AND ', $escape = NULL)
{
    ...

        if (is_null($v) && ! $this->_has_operator($k))
        {
            // value appears not to have been set, assign the test to IS NULL
            $k .= ' IS NULL';
        }

        ...
}

And system/database/DB_driver.php

/**
 * Tests whether the string has an SQL operator
 *
 * @access  private
 * @param   string
 * @return  bool
 */
function _has_operator($str)
{
    $str = trim($str);
    if ( ! preg_match("/(\s|<|>|!|=|is null|is not null)/i", $str))
    {
        return FALSE;
    }

    return TRUE;
}

As a result you could pass just first parameter to where() method and if first operator of this method has a sub string is not null it will be left untouched.

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