We use NULL all the time with MyISAM tables, and I've never noticed a problem.
Well, there was one bizarre bit of business that's already been mentioned: my predecessor actually put the string "NULL" into a field, and since it looks the same in the MySQL client that gave me a devil of a time. Regards, Jerry Schwartz Global Information Incorporated 195 Farmington Ave. Farmington, CT 06032 860.674.8796 / FAX: 860.674.8341 > -----Original Message----- > From: Kevin Hunter [mailto:[EMAIL PROTECTED] > Sent: Tuesday, May 01, 2007 11:37 AM > To: John Kebbel > Cc: MySQL List > Subject: Re: IS NULL Question > > At 9:06p -0400 on 30 Apr 2007 John Kebbel wrote: > > I'm having problems understanding NULL. I grasp what a NULL > value is, > > A NULL value is rather an oxymoron. It'd be more accurate to say > that NULL means "absence of a value". > > > 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.) > > Caveat emptor: I haven't tested this in about a year. > > Are you perchance using a table type of MyISAM? I seem to recall > that MyISAM has a hard time actually representing NULL internally. > [ ... Thinks for a minute ... ] I remember something about spaces, > like, I think I did > > INSERT ( val1, val2, NULL ) INTO myTable; > > and was only able to get the tuples back when I did > > SELECT * FROM myTable WHERE col3 = ' '; -- a space character > > If this is the case, you might consider using a different > table type, > such as InnoDB. > > HTH, > > Kevin > > -- > MySQL General Mailing List > For list archives: http://lists.mysql.com/mysql > To unsubscribe: > http://lists.mysql.com/[EMAIL PROTECTED] > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
