MySQL 更改表查询的正确语法是什么 - what is the correct syntax for MySQL alter table query?

what is the correct syntax for MySQL alter table query?

本文关键字：语法是什么查询 MySQL | 更新日期: 2024-06-29

当我尝试运行以下 mysqli 调用时

$strSQL3=mysqli_query($connection," alter table mark_list add column 'mark' int(2) " ) or die(mysqli_error($connection));

返回错误

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near `mark int(2)` at line 1

单引号（ ' ）表示字符串文字。对象名称（如列）不是字符串 - juts 会丢失引号：

$strSQL3 = mysqli_query($connection ,"alter table mark_list add column mark int(2)" ) or die(mysqli_error($connection));

尝试将"mark"更改为如下所示的标记：

    $strSQL3=mysqli_query($connection,
             " alter table mark_list add column mark int(2) " ) 
              or die(mysqli_error($connection));

只需删除'标记附近的引号

$strSQL3=mysqli_query($connection," alter table mark_list add column mark int(2) " ) or die(mysqli_error($connection));