Syntax:
expr REGEXP pat expr RLIKE pat

Performs a pattern match of a string expression expr against a pattern
pat. The pattern can be an extended regular expression. The syntax for
regular expressions is discussed in [regexp]. Returns 1 if expr matches
pat; otherwise it returns 0. If either expr or pat is NULL, the result
is NULL. RLIKE is a synonym for REGEXP, provided for mSQL
compatibility.

The pattern need not be a literal string. For example, it can be
specified as a string expression or table column.

Note: Because MySQL uses the C escape syntax in strings (for example,
`\n' to represent the newline character), you must double any `\' that
you use in your REGEXP strings.

REGEXP is not case sensitive, except when used with binary strings.
