1. 查看

1.1 查看uuid

select @@server_uuid；
+--------------------------------------+
| @@server_uuid                        |
+--------------------------------------+
| ea5085ce-ac82-11ea-9dcd-005056b25447 |
+--------------------------------------+
1 row in set (0.00 sec)

1.2 查看binlog事件

show binlog events;
+---------------------------------+-----+----------------+------------+-------------+---------------------------------------+
| Log_name                        | Pos | Event_type     | Server_id  | End_log_pos | Info                                  |
+---------------------------------+-----+----------------+------------+-------------+---------------------------------------+
| 161cc2f8_fKGvn001-binlog.000001 |   4 | Format_desc    | 3232235526 |         123 | Server ver: 5.7.22-log, Binlog ver: 4 |
| 161cc2f8_fKGvn001-binlog.000001 | 123 | Previous_gtids | 3232235526 |         154 |                                       |
+---------------------------------+-----+----------------+------------+-------------+---------------------------------------+
2 rows in set (0.01 sec)

1.3 查看binlog日志

mysql> show binary logs;
±--------------------------------±----------+
| Log_name | File_size |
±--------------------------------±----------+
| 161cc2f8_fKGvn001-binlog.000001 | 154 |
±--------------------------------±----------+
1 row in set (0.00 sec)

1.4 flush

flush;
help flush;

flush slow logs;
flush local slow logs;

flush binary logs;
flush local binary logs;

flush privileges;
flush local privileges;

查看用户权限

$ show grants;
$  show grants for test;

查看表

$ show table mysql_user;
$ show create table mysql_user;

2 查询

2.1 查询在A表不在B表的数据

假设有A、B两张表。

如果查询在A表中存在，但是在B表中不存在的记录，应该如何操作？
A表

id

1

2

3

4

5

B表

id

a_id

1

3

2.1.1 子查询方法

select A.* from A where A.id not in(select B.a_id from B);

2.1.2 使用join方法

select * from A left join B on A.id = B.a_id;