Mysql.user the meaning of the% of host in table

The Host column specifies the IP that is used to allow the user to log on, such as User=root host=192.168.1.1. This means that the root user can only access it through the 192.168.1.1 client.
and% is a wildcard, if host=192.168.1.%, then it means that the IP address prefix is "192.168.1." Clients can connect. If host=%, indicates that all IPs have connection permissions. 、
This is why when the remote connection is turned on, most people directly change the host to%, for the sake of convenience.