Characters and classes used by the REGEXP and NOT REGEXP operators (or RLIKE and NOT RLIKE, which are synonyms) : REGEXP « Regular Expressions « MySQL Tutorial

'.' matches any single character.

A character class '[...]' matches any character within the brackets.

For example, '[abc]' matches 'a', 'b', or 'c'.

To name a range of characters, use a dash.

'[a-z]' matches any letter, whereas '[0-9]' matches any digit.

'*' matches zero or more instances of the thing preceding it.

For example, 'x*' matches any number of 'x' characters.

'[0-9]*' matches any number of digits.

'.*' matches any number of anything.

A REGEXP pattern match succeeds if the pattern matches anywhere in the value being tested.

A LIKE pattern match succeeds only if the pattern matches the entire value.

'^' matches the beginning of the pattern.

'$' matches the end of the pattern.