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From:Paul DuBois Date:November 11 2004 2:24am
Subject:Re: quote and null
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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
Thread
quote and nullToro Hill10 Nov
  • Re: quote and nullEric Bergen11 Nov
  • Re: quote and nullPaul DuBois11 Nov
    • Re: quote and nullMichael Stassen11 Nov
    • Re: quote and nullPaul DuBois12 Nov
  • Re: quote and nullMichael Stassen11 Nov
    • Re: quote and nullPaul DuBois11 Nov
      • Re: quote and nullMichael Stassen11 Nov
        • Re: quote and nullPaul DuBois11 Nov
          • Re: quote and nullMichael Stassen11 Nov