错误日志如下：
170324 11:18:41 mysqld_safe Logging to '/Applications/MAMP/logs/mysql_error.log'.
170324 11:18:41 mysqld_safe Starting mysqld daemon with databases from /Library/Application Support/appsolute/MAMP PRO/db/mysql56
2017-03-24 11:18:41 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2017-03-24 11:18:41 0 [Note] --secure-file-priv is set to NULL. Operations related to importing and exporting data are disabled
2017-03-24 11:18:41 0 [Note] /Applications/MAMP/Library/bin/mysqld (mysqld 5.6.35) starting as process 2644 ...
2017-03-24 11:18:41 2644 [Warning] Setting lower_case_table_names=2 because file system for /Library/Application Support/appsolute/MAMP PRO/db/mysql56/ is case insensitive
2017-03-24 11:18:41 2644 [Note] Plugin 'FEDERATED' is disabled.
2017-03-24 11:18:41 2644 [Note] InnoDB: Using atomics to ref count buffer pool pages
2017-03-24 11:18:41 2644 [Note] InnoDB: The InnoDB memory heap is disabled
2017-03-24 11:18:41 2644 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2017-03-24 11:18:41 2644 [Note] InnoDB: Memory barrier is not used
2017-03-24 11:18:41 2644 [Note] InnoDB: Compressed tables use zlib 1.2.8
2017-03-24 11:18:41 2644 [Note] InnoDB: Using CPU crc32 instructions
2017-03-24 11:18:41 2644 [Note] InnoDB: Initializing buffer pool, size = 128.0M
2017-03-24 11:18:41 2644 [Note] InnoDB: Completed initialization of buffer pool
2017-03-24 11:18:41 2644 [Note] InnoDB: Highest supported file format is Barracuda.
2017-03-24 11:18:41 2644 [Note] InnoDB: The log sequence numbers 1704703 and 1704703 in ibdata files do not match the log sequence number 1704713 in the ib_logfiles!
2017-03-24 11:18:41 2644 [Note] InnoDB: Database was not shutdown normally!
2017-03-24 11:18:41 2644 [Note] InnoDB: Starting crash recovery.
2017-03-24 11:18:41 2644 [Note] InnoDB: Reading tablespace information from the .ibd files...
2017-03-24 11:18:41 2644 [ERROR] InnoDB: Attempted to open a previously opened tablespace. Previous tablespace db_patients/tb_patients uses space ID: 3 at filepath: ./db_patients/tb_patients.ibd. Cannot open tablespace mysql/slave_relay_log_info which uses space ID: 3 at filepath: ./mysql/slave_relay_log_info.ibd
2017-03-24 11:18:41 7fffcc2c73c0 InnoDB: Operating system error number 2 in a file operation.
InnoDB: The error means the system cannot find the path specified.
InnoDB: If you are installing InnoDB, remember that you must create
InnoDB: directories yourself, InnoDB does not create them.
InnoDB: Error: could not open single-table tablespace file ./mysql/slave_relay_log_info.ibd
InnoDB: We do not continue the crash recovery, because the table may become
InnoDB: corrupt if we cannot apply the log records in the InnoDB log to it.
InnoDB: To fix the problem and start mysqld:
InnoDB: 1) If there is a permission problem in the file and mysqld cannot
InnoDB: open the file, you should modify the permissions.
InnoDB: 2) If the table is not needed, or you can restore it from a backup,
InnoDB: then you can remove the .ibd file, and InnoDB will do a normal
InnoDB: crash recovery and ignore that table.
InnoDB: 3) If the file system or the disk is broken, and you cannot remove
InnoDB: the .ibd file, you can set innodb_force_recovery > 0 in my.cnf
InnoDB: and force InnoDB to continue crash recovery here.
170324 11:18:41 mysqld_safe mysqld from pid file /Applications/MAMP/tmp/mysql/mysql.pid ended
其中关键的一行是：
InnoDB: Attempted to open a previously opened tablespace. Previous tablespace db_patients/tb_patients uses space ID: 3 at filepath: ./db_patients/tb_patients.ibd. Cannot open tablespace mysql/slave_relay_log_info which uses space ID: 3 at filepath: ./mysql/slave_relay_log_info.ibd
解决办法：
一、打开MAMP PRO，点击主界面左侧LANGUAGES中PHP，右侧Extensions分类中点击Manually enable other extensions右侧按钮（或者打开菜单栏File->Edit Template->MySQL->7.1.1（选择你的版本）），这时打开了一个文本，找到
[mysqld]
注意带上中括号，在[mysqld]下面加一行：
innodb_force_recovery = 1
二、启动mySQL，成功后再关闭；
三、重新打开那个文本，删除添加的那一行；
四、再打开mySQL，完毕。
