Problem when saving with emoji

PS: Following these instructions solved the issue for me: https://stackoverflow.com/questions/6115612/how-to-convert-an-entire-mysql-database-characterset-and-collation-to-utf-8

I didn't have sufficient privileges to just run a SQL command in phpMyAdmin, so I did a modified version of what is given there.

I logged into my server via the shell, then generated a list of tables with this:

mysql -e "show full tables where Table_Type = 'BASE TABLE'"

Then I converted that output to a .sql file (which I named "change_charset.sql") where each table gets a line like this:

ALTER TABLE ReplaceWithTableName CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

At the very top of that file put this line:

ALTER DATABASE DATABASENAME CHARACTER SET utf8 COLLATE utf8_unicode_ci;

Then I uploaded that change_charset.sql file to my server and figured out its path, then executed this command:

mysql -u awww -pPASSWORD -h HOST -P PORTNUMBER DATABASENAME < /sites/user/change_charset.sql

If you are going to follow my steps, replace PASSWORD, HOST, PORTNUMBER (if needed; if not needed, remove "-P PORTNUMBER"), and DATABASENAME in the above MySQL command with the equivalents for your own server. You can find these in your wp-config.php file in your root HTTP/web directory.