补充MySQL官网知识--解锁Online VARCHAR字段扩展与Index的关系大家可以先看本文的结论【即 4. 总结】,如有兴趣再顺读。修改的语法如下The number of length bytes required by a VARCHAR column must remain the same. For VARCHAR columns of 0 to 255 bytes in size, one length byte is required to encode the value. For VARCHAR columns of 256 bytes in size or m