php - SQL Alter Table 语法错误

Question

--Rev19
ALTER TABLE `staff` MODIFY `role` enum('admin', 'employee', 'guest'); 
ALTER TABLE `staff` ALTER `role` SET DEFAULT 'guest';

它说:

#1064 - 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 '--Rev19
ALTER TABLE `staff` MODIFY `role` enum('admin', 'employee', 'guest')' at line 1 

这里有什么问题吗？附带说明一下，为什么 SQL 错误报告必须如此糟糕，大多数语言会告诉您 SQL 只是说的特定语法错误，请查看手册。

Answer 1

来自手册:

From a “-- ” sequence to the end of the line. In MySQL, the “-- ” (double-dash) comment style requires the second dash to be followed by at least one whitespace or control character (such as a space, tab, newline, and so on).

所以只需在 -- 之后添加一个空格就可以了。