Syntax:
INET_ATON(expr)

Given the dotted-quad representation of an IPv4 network address as a
string, returns an integer that represents the numeric value of the
address in network byte order (big endian). INET_ATON() returns NULL if
it does not understand its argument.

URL: https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html

