Other References

The last three references for this appendix include Table B.17, how to store special characters in a database; Table B.18, how to weight keywords in a binary-mode full-text search; and Table B.19, significant characters for regular expressions.

Table B.17. These characters all have special meanings when used in queries. The letters are all case-sensitive! The percentage character and the underscore are necessary because these characters, when not escaped, can be used as wildcards in searches.

Escape Characters
Character	Meaning
\'	Single quotation mark
\'	Double quotation mark
\b	Backspace
\n	Newline
\r	Carriage return
\t	Tab
\\	Backslash
\%	Percentage character
\_	Underscore character

Table B.18. As of version 4 of MySQL, you can perform full-text searches in binary mode, using these symbols.

Special Boolean Mode Characters
Character	Meaning	Example	Matches
+	Word is required	+punk rock	punk is required and rock is optional.
-	Word must not be present	+punk -rock	punk is required and rock cannot be present.
""	A literal phrase	"punk rock"	Occurrences of the phrase punk rock are weighted.
<	Less important	<punk +rock	rock is required and punk is less significant.
>	More important	>punk +rock	rock is required but punk is more significant.
()	Creates groups	(>punk roll) +rock	rock is required, both punk and roll are optional, but punk is weighted more.
~	Detracts from relevance	+punk ~rock	punk is required, and the presence of rock devalues the relevance (but rock is not excluded).
*	Allows for wildcards	+punk +rock*	punk and rock are required, but rocks, rocker, rocking, etc., are counted.

Table B.19. When using REGEX and NOT REGEX, you'll need to define patterns with the characters listed here.

Special Regular Expression Characters
Character	Matches
.	Any single character
q?	Zero or one q
q*	Zero or more q's
q+	At least one q
q{x}	Exactly x instances of q
q{x,}	At least x instances of q
q{,x}	Up to x instances of q
q{x,y}	Between x and y instances of q
^q	Starts with q
q$	Ends with q
(pqr)	Grouping (matches pqr)
q|z	Either q or z
[]	Character classes (e.g., [a-z], [0-9])
\	Escapes a special character (\., \*, etc.)