You need (at least one of) the SUPER, SYSTEM_VARIABLES_ADMIN or SESSION_VARIABLES_ADMIN privilege(s) for this operation

Deutsches Forum
19

→ The ENCODE() and DECODE() functions are deprecated in MySQL 5.7, and should no longer be used. Expect them to be removed in a future MySQL release.
https://dev.mysql.com/doc/refman/5.7/en/encryption-functions.html