MySQL alter table查询的正确语法是什么？

Question

While I try to run the following mysqli call

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

returns error

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

Answer 1

Single quotes ( ' ) denote string literals. Object names (such as columns), are not strings - juts lose the quotes:

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

Answer 2

Try changing 'mark' to mark like this:

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

Answer 3

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));