Syntax:
INET_NTOA(expr)

Given a numeric IPv4 network address in network byte order, returns the
dotted-quad string representation of the address as a nonbinary string
in the connection character set. INET_NTOA() returns NULL if it does
not understand its argument.

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

