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From:John Kebbel Date:May 1 2007 1:06am
Subject:IS NULL Question
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I'm having problems understanding NULL. I grasp what a NULL value is,
but I can't get NULL to perform correctly. For instance, if I do a
Select statement, I see that I have columns with a NULL value.

select first, last, suffix  from persons LIMIT 5;
+-----------+----------+--------+
| first     | last     | suffix |
+-----------+----------+--------+
| Benjamin  | Page     | NULL   |
| Jonathan  | Watson   | NULL   |
| Jose      | Thorson  | NULL   |
| Alejandro | Nickels  | NULL   |
| Griselda  | Richards | NULL   |
+-----------+----------+--------+
5 rows in set (0.01 sec)

Logically, it seems that a Select statement should find these five plus
any other NULL values in the suffix column. However, such a select
statment returns an empty set.

mysql> select first, last, suffix  from persons where suffix IS NULL;
Empty set (0.00 sec)

Does anyone see what I'm doing wrong? (Thanks in advance for any help.)



Thread
IS NULL QuestionJohn Kebbel1 May
  • Re: IS NULL QuestionJeremy Cole1 May
    • Re: IS NULL QuestionJohn Kebbel1 May
  • Re: IS NULL QuestionMartijn Tonies1 May
    • Re: IS NULL QuestionLucas.CTR.Heuman1 May
  • Re: IS NULL QuestionKevin Hunter1 May
    • Re: IS NULL QuestionGerald L. Clark1 May
      • Re: IS NULL QuestionKevin Hunter1 May
    • RE: IS NULL QuestionJerry Schwartz1 May
      • Re: IS NULL QuestionBaron Schwartz1 May
    • batch modeCharles Brown2 May
      • Re: batch modeMogens Melander2 May
        • Re: batch modeMogens Melander2 May