您可以尝试以下操作：

$csv = $_FILES['file']['tmp_name'];

$handle = fopen($csv,"r");
while (($row = fgetcsv($handle, 10000, ",")) != FALSE) //get row vales
{
    print_r($row); //rows in array

   //here you can manipulate the values by accessing the array

}

这是我使用的代码：在视图上：

<form action="<?php echo base_url('Controller/get_content'); ?>"  method="POST" enctype="multipart/form-data">
    <input type="file" class="custom-file-input" id="csv_file" name="csv_file"> 
    <label class="custom-file-label" for="csv_file">Choose CSV file</label>
    <button class="btn btn-success" type="submit"> Import</button>
</form>

在控制器上：

public function get_content(){
    $csv = $_FILES['csv_file']['tmp_name'];
    $handle = fopen($csv,"r");
    while (($row = fgetcsv($handle, 10000, ",")) != FALSE)
    {
        //row should have same structure as database
        $add = $this->model->add($row);
    }
                
    redirect('/import_page', 'refresh');
}

在模型上：

public function add($data){
   return $this->db->insert("table_csv", $data);
}