复制时间戳值从一列到另一列失败

Question

我有一个表格，其中包含两个时间戳字段 -

<div class="row justify-content-center">
  <h1>New User</h1>
</div>

<div class='row justify-content-center'>
  <div class='col-6'>
    <form [formGroup]='regForm'
    (ngSubmit)="onSubmit(regForm.value)"
    [class.error]="!regForm.valid && regForm.touched"
    >
      <div class='form-group'
        [class.error]="!regForm.get('name').valid && regForm.get('name').touched">
        <label>Name</label>
        <input type="text" class='form-control' [formControl]="regForm.controls['name']">
        <div *ngIf="regForm.controls['name'].hasError('required')" class="invalid-feedback">Name is required</div>
      </div>
      <div class='form-group'>
        <label>Email</label>
        <input type="email" class='form-control'>
      </div>
      <div class='form-group'>
        <label>Password</label>
        <input type="password" class='form-control'>
      </div>
      <div class='form-group'>
        <label>Confirmation</label>
        <input type="password" class='form-control'>
      </div>
      <button type="submit" class='btn btn-default'>Submit</button>
    </form>
  </div>
</div>

我使用

插入了两行

CREATE TABLE `test` 
(`id` INT NOT NULL AUTO_INCREMENT , 
`first_date` TIMESTAMP NULL , 
`second_date` TIMESTAMP on update CURRENT_TIMESTAMP() NULL , 
PRIMARY KEY (`id`)) ENGINE = InnoDB;

现在，我需要将第二个日期值复制到第一个日期列，但是当我尝试更新查询时，日期值都会更新到今天的日期。

INSERT INTO `test` (`id`, `first_date`, `second_date`) 
VALUES (NULL, NULL, '2017-10-18 17:02:14'), (NULL, NULL, '2017-10-18 17:02:14');

不知何故，second_date的update test set first_date = second_date where id=<row_id> id | first_date | second_date ---------------------------------------------- 3 | 2017-11-17 16:09:03 | 2017-11-17 16:09:29 --> This value was 4 | NULL | 2017-10-18 17:02:14 "2017-10-18 17:02:14" 5 | NULL | 2017-10-18 17:02:14 before the update query. 属性在这里造成了问题。如何从第二列复制值而不影响on update CURRENT_TIMESTAMP()的现有值？

Answer 1

以下查询应该可以帮助您从第二列复制值而不影响second_date的现有值：

UPDATE test SET first_date = second_date , second_date = second_date WHERE  id=<row_id>