At 21:11 -0500 11/10/04, Michael Stassen wrote:
>Toro Hill wrote:
>
>>Hi all.
>>I have question about how the function quote() works with NULL
>>values. Here is what the mysql manual say:
>>---
>>QUOTE(str)
>>Quotes a string to produce a result that can be used as a properly
>>escaped data value in an SQL statement. The string is returned
>>surrounded by single quotes and with each instance of single quote
>>(`''), backslash (`\'), ASCII NUL, and Control-Z preceded by a
>>backslash. If the argument is NULL, the return value is the word
>>``NULL'' without surrounding single quotes. The QUOTE() function
>>was added in MySQL 4.0.3.
>>
>>mysql> SELECT QUOTE('Don\'t!');
>> -> 'Don\'t!'
>>mysql> SELECT QUOTE(NULL);
>> -> NULL
>>---
>>Now after reading this I thought that select quote(NULL) would
>>return the string 'NULL' (without quotes) and not the NULL value.
>>However, this is not true on the version of mysql that I'm using:
>
>You've misunderstood, then. Without the quotes, NULL is the NULL
>value, not a string. You have to have quotes to be a string! NULL
>is NULL, 'NULL' is a string. MySQL is doing exactly what the manual
>says.
It's not. The manual says that if the argument is NULL, the return
value is _the word_ NULL without quotes. In other words, it's a string
but the string doesn't include surrounding quotes.
QUOTE() is supposed to produce values similar to what you get with the
DBI quote() function.
--
Paul DuBois, MySQL Documentation Team
Madison, Wisconsin, USA
MySQL AB, www.mysql.com
