Syntax:
COMPRESS(string_to_compress)

Compresses a string and returns the result as a binary string. This
function requires MySQL to have been compiled with a compression
library such as zlib. Otherwise, the return value is always NULL. The
return value is also NULL if string_to_compress is NULL. The compressed
string can be uncompressed with UNCOMPRESS().

URL: https://dev.mysql.com/doc/refman/8.0/en/encryption-functions.html

