$this->db
        ->select('*')
        ->from('library')
        ->where('library.rating >=',$form['slider'])
        ->where('library.votes >=','1000')
        ->where('library.language !=','German')
        ->where('library.available_until >=',date("Y-m-d H:i:s"))
        ->or_where('library.available_until =',"00-00-00 00:00:00")
        ->where('library.release_year >=',$year_start)
        ->where('library.release_year <=',$year_end)
        ->join('rating_repo','library.id = rating_repo.id')

所以,我遇到的麻烦是与我的or_where.我想要或仅限于available_until字段.然而,目前,我正在获得一种德语不是我想要的语言的结果.我如何将我的or_where过滤器限制在available_until字段？