# Match String Pattern:  RLIKE
__*RLIKE operation*__
__*REGEXP operation*__
__*regular expression*__
+ Regular expressions are a powerful method to specify patterns for complex searches
+ `RLIKE, REGEXP` operator: `expression RLIKE|REGEXP 'regexp-pattern'`  
+ `\` As an escape character
+ `()` Group multiple regular expression elements
+ For example:
  + `^`: the beginning of the string
  + `$`: end of string
  + `.`: any single character
  + `x*`: zero or more `x`  
  + `x+`: one or more `x`  
  + `x?`: zero or one `x`  

------------------------------------------------------------
Other modes:
  `|`: Alternate
  `{n}` :n times
  `{m,n}` :m to n times
  `[ ]`: contains one character in square brackets
  `[^ ]`: Does not contain any of the characters in square brackets
  `[[:class:]]`: a character in a character class
For more information on regular expressions, see the URL at `http://dev.mysql.com/doc/mysql/en/regexp.html` .