我试图返回个人电话号码为空（如"“中）或NULL的记录。请检查此代码

$this->db->select('i.id, i.name, i.phone, b.date')
                          ->from('bookings AS b')
                          ->join('individuals AS i', 'b.individual_id = i.id')
                          ->where('b.status', 'confirmed')
                          ->where('b.date >=', '2022-09-12')
                          ->where('b.date <=', '2023-01-15')
                          ->where('i.phone = "" OR i.phone IS NULL')
                          ->order_by('b.date', 'ASC')
                          ->get();

结果是它为Phone返回NULL值，但where子句中的日期范围被覆盖，该字段的值也为NULL。
这让我想起了

object(stdClass)[129]
      public 'id' => string '52393' (length=5)
      public 'name' => string 'Mrs Janet dooley' (length=17)
      public 'phone' => null
      public 'date' => null
  1 => 
    object(stdClass)[198]
      public 'id' => string '32277' (length=5)
      public 'name' => string 'Ms Rita molongi' (length=16)
      public 'phone' => null
      public 'date' => null