MySQL 报错：[Err] 1071 Specified key was too long; max key length is 767 bytes

[Err] 1071 - Specified key was too long; max key length is 767 bytes

这个会出现在MySQ5.7以下版本 因为没有启用innodb_large_prefix

MySQL 5.6：

 MySQL 5.7：

简单办法：如果要求不是很高 ，也可以直接把表字段varchar(255)设置为varchar(64) 

另外一种：修改配置 （重启服务会失效）

mysql> show variables like '%innodb_large_prefix%';
+---------------------+-------+
| Variable_name       | Value |
+---------------------+-------+
| innodb_large_prefix | OFF   |
+---------------------+-------+
1 row in set

mysql> set global innodb_large_prefix=on;
Query OK, 0 rows affected

mysql> show variables like '%innodb_large_prefix%';
+---------------------+-------+
| Variable_name       | Value |
+---------------------+-------+
| innodb_large_prefix | ON    |
+---------------------+-------+
1 row in set