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From:Paul DuBois Date:September 15 2003 4:01pm
Subject:Re: Does NULL == ""?
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At 11:00 AM -0400 9/15/03, Randy Chrismon wrote:
>The MySQL documentation confuses me a bit. If I create a table with
>property NOT NULL and default "", does that mean that a record with a
>column so defined will have a zero-length string in that column if I
>don't provide a value? I guess what I'm asking is whether there's a
>difference between a field with NULL in it and a field with a
>zero-length ("") string in it.

Other responses have given a lot of informatin that I'll not repeat here,
but you can test whether the two values are equal like this:

mysql> SELECT "" IS NULL;
+------------+
| "" IS NULL |
+------------+
|          0 |
+------------+

Guess not. :-)

>
>Thanks.
>
>Randy


-- 
Paul DuBois, Senior Technical Writer
Madison, Wisconsin, USA
MySQL AB, www.mysql.com

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Thread
Does NULL == ""?Randy Chrismon15 Sep
  • Re: Does NULL == ""?Bruce Feist15 Sep
  • RE: Does NULL == ""?Mark Richards15 Sep
  • Re: Does NULL == ""?Brent Baisley15 Sep
    • Re: Does NULL == ""?Keith C. Ivey15 Sep
  • Re: Does NULL == ""?Paul DuBois15 Sep
Re: Does NULL == ""?Alec.Cawley15 Sep
  • RE: Does NULL == ""?Mark Richards15 Sep
Re: Does Null == ""?Randy Chrismon15 Sep
  • RE: Does Null == ""?Mark Richards15 Sep
  • Re: Does Null == ""?Bob Hall16 Sep
    • Re: Does Null == ""?Bruce Feist16 Sep
      • Re: Does Null == ""?Dan Nelson16 Sep
        • Re: Does Null == ""?Bruce Feist16 Sep
          • Re: Does Null == ""?Bob Hall16 Sep
        • Re: Does Null == ""?Bob Hall16 Sep
      • RE: Does Null == ""?Jon Frisby16 Sep
        • Re: Does Null == ""?Bruce Feist16 Sep
          • RE: Does Null == ""?Jon Frisby16 Sep
            • Re: Does Null == ""?Bruce Feist16 Sep
              • RE: Does Null == ""?Jon Frisby16 Sep
              • Re: Does Null == ""?Bob Hall17 Sep
        • Re: Does Null == ""?Bob Hall16 Sep
      • Re: Does Null == ""?Bob Hall16 Sep
    • Re: Does Null == ""?Bob Hall17 Sep
      • Re: Does Null == ""?Bruce Feist18 Sep
        • Re: Does Null == ""?Bob Hall18 Sep
  • Re: Does Null == ""?Haydies18 Sep
    • Re: Does Null == ""?Bob Hall18 Sep