DB Active Record: where / or_where return different result

[eluser]tkaw220[/eluser]
Hi,

When working with Active Record, I found below issue:

1)

Code:

$q = $this->db
           ->where('format', 'reader')
           ->or_where('format', 'reader with 3D goggles')
           ->order_by('brand, format, title', 'asc')
           ->get('products');

Query:

Code:

SELECT * FROM (`products`) WHERE `format` = 'reader' OR `format` = 'reader with 3D goggles' ORDER BY `brand`, `format`, `title` asc

Return products properly.

2)

Code:

$q = $this->db
           ->where('format', 'reader')
           ->or_where(array('format' => 'reader', 'format' => 'reader with 3D goggles'))
           ->order_by('brand, format, title', 'asc')
           ->get('products');

Query:

Code:

SELECT * FROM (`products`) WHERE `format` = 'reader' OR `format` = 'reader with 3D goggles' ORDER BY `brand`, `format`, `title` asc

Return only products match the second parameter, which is reader with 3D goggles.

I do not understand how two codes generated one same SQL query, but return result differently. Would appreciate if someone could clarify this.

Thank you for your time.