MYSQL Character Sets and Collations
Which CHARACTER SET and COLLATION?
There are dozens of character sets with hundreds of collations. (A given collation belongs to only one character set.)
See the output of SHOW COLLATION;.
There are usually only 4 CHARACTER SETs that matter:
All include English characters, encoded identically. utf8 is a subset of utf8mb4.
.Use utf8mb4 for any TEXT or VARCHAR column that can have a variety of languages in it.
.Use ascii (latin1 is ok) for hex strings (UUID, MD5, etc) and simple codes (country_code, postal_code, etc).
utf8mb4 did not exist until version 5.5.3, so utf8 was the best available before that.
Outside of MySQL, "UTF8" means the same things as MySQL's utf8mb4, not MySQL's utf8.
Collations start with the charset name and usually end with _ci for "case and accent insensitive" or _bin for "simply compare the bits.
The 'latest' utf8mb4 collation is utf8mb4_unicode_520_ci, based on Unicode 5.20. If you are working with a single language, you might want, say, utf8mb4_polish_ci, which will rearrange the letters slightly, based on Polish conventions.