Character Sets and Collations - Mastering phpMyAdmin 2.8 for Effective MySQL Management - page 240

There is no MySQL Charset selector. The character set defined in the chosen
Language (here English iso-8859-1) will be used to communicate with MySQL.
Choosing the Effective Character Set
Now, we set $cfg['AllowAnywhereRecoding'] to TRUE . Then we choose English
(en-utf-8) in the Language selector. The Home page has changed:
The MySQL Charset choice appears only if the current chosen Language uses utf-8
encoding. From now on, every communication that occurs between the web server
and the MySQL server will use this MySQL character set.
The choice of character set is remembered for 30 days using
a cookie mechanism. Depending on where the cookies are
stored (on the local computer or on a network server), the
character set may need to be chosen again if we log in to
phpMyAdmin from another computer.
The Impact of Switching
When we choose a character set, all the data stored in MySQL will be recoded with
this character set. If we subsequently change the character set used by phpMyAdmin,
we will get incorrect results when fetching the data. There is no easy way of finding
which character set was used to store a particular row of data.