UNQUOTE()

USAGE

UNQUOTE(string)

DETAILS

UNQUOTE() is a string function that returns a string with removed surrounding quotation marks and removed backslash escapes.

The input argument can be surrounded by either single quotes or double quotes. If the starting character and ending character are not a single/double quote or they don't match, the string is returned unchanged.

When quotes are removed, the return value is also modified to remove backslash escaping: the way to get a backslash in the result is for the input to contain 2 backslash characters in a row.

Certain improperly escaped inputs might return an unexpected output, such as a 1-character string of a quote turning into an empty string. However, properly encoded quoted strings always return a properly unquoted string.

For the reverse operation, see QUOTE().

A NULL is returned if the argument is NULL.

EXAMPLES

SET @chk = '"testing \\"one two\\"!"';
SELECT @chk, UNQUOTE(@chk)\G

*************************** 1. row ***************************
         @chk: "testing \"one two\"!"
UNQUOTE(@chk): testing "one two"!

SET @chk = QUOTE('I \\ can\'t \\ decide.');
SELECT @chk, UNQUOTE(@chk)\G

*************************** 1. row ***************************
         @chk: 'I \\ can\'t \\ decide.'
UNQUOTE(@chk): I \ can't \ decide.

SET @chk = '"hi\'';
SELECT @chk, UNQUOTE(@chk)\G

*************************** 1. row ***************************
         @chk: "hi'
UNQUOTE(@chk): "hi'

SELECT UNQUOTE('"'), UNQUOTE('"\\"');

+--------------+-----------------+
| UNQUOTE('"') | UNQUOTE('"\\"') |
+--------------+-----------------+
|              |                 |
+--------------+-----------------+

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