One of the things I like the most in MySQL is the possibility to use regular expressions in the SQL queries.

A very simple example illustrating this is to select all the records from MyTable for which MyField starts with "A"

SELECT * FROM MyTable WHERE MyField REGEXP '^a';

Please take a look to the list below in order to find more information for the available options

MySQL Regular Expressions

*
Matches zero or more instances of the string preceding it

+
Matches one or more instances of the string preceding it

?
Matches zero or one instances of the string preceding it

.
Matches any single character

[xyz]
Matches any of x, y, or z (the characters within the brackets)

[A-Z]
Matches any uppercase letter

[a-z]
Matches any lowercase letter

[0-9]
Matches any digit

^
Anchors the match from the beginning

$
Anchors the match to the end

|
Separates strings in the regular expression

{n,m}
String must occur at least n times, but no more than n

{n}
String must occur exactly n times

{n,|
String must occur at least n times