Syntax:
IS_IPV4_COMPAT(expr)

This function takes an IPv6 address represented in numeric form as a
binary string, as returned by INET6_ATON(). It returns 1 if the
argument is a valid IPv4-compatible IPv6 address, 0 otherwise.
IPv4-compatible addresses have the form ::ipv4_address.

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

