php - 将datetime插入codeigniter

我做错什么了？尝试将date time插入到我的数据库中时，所有字段都工作，只是日期时间不起作用。我试了好几个小时，什么都没用。
看法

<fieldset>
    <legend>Account Information</legend>
    <?php
    echo form_open('banks/create_bank');
    echo form_input('bank_name', set_value('bank_name', 'Account Name'));
    echo form_input('interest', set_value('interest', 'Interest'));
    echo form_input('start_amount', set_value('start_amount', 'Starting Balance'));
    echo form_input('length', set_value('length', 'Length'));
    echo form_dropdown("<type ='date' name='start_date'>") ;
//    echo form_input("<type ='date' name='start_date'>") ;
//    echo form_checkbox("<type ='date' name='start_date'>") ;
//    echo form_fieldset("<type ='date' name='start_date'>") ;
//    echo form_multiselect("<type ='date' name='start_date'>") ;
    echo form_submit('submit', 'Add Bank ')
        ?>
</fieldset>

模型

$new_bank_acc_insert_data = array(
            'bank_name' => $this->input->post('bank_name'),
            'interest' => ($this->input->post('interest') / 100),
            'start_amount' => $this->input->post('start_amount'),
            'length' => $this->input->post('length'),
            'start_date' => $this->input->post('start_date'),
            'mem_id' => $this->session->userdata('id')
        );

最佳答案

改变

$new_bank_acc_insert_data = array(
            'bank_name' => $this->input->post('bank_name'),
            'interest' => ($this->input->post('interest') / 100),
            'start_amount' => $this->input->post('start_amount'),
            'length' => $this->input->post('length'),
            'start_date' => $this->input->post('start_date'),
            'mem_id' => $this->session->userdata('id')
        );

到

$new_bank_acc_insert_data = array(
            'bank_name' => $this->input->post('bank_name'),
            'interest' => ($this->input->post('interest') / 100),
            'start_amount' => $this->input->post('start_amount'),
            'length' => $this->input->post('length'),
            'start_date' => date('Y-m-d H:i:s',strtotime($this->input->post('start_date'))),
            'mem_id' => $this->session->userdata('id')
    );