I ran into the issue where data had been written, and then a Null was written.
The presence of Null in a field may not in fact guarantee that data has never been written. -m- -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Monday, September 15, 2003 11:12 To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: Does NULL == ""? No, NULL is not the same as the empty string. NULL, for any class of field, means that no data has ever been written there. Tests involving NULL other than IS NULL and IS NOT NULL will return NULL. Thus "" < "a" returns 1 (true) whereas NULL < "a" returns NULL, which will always be regarded as a "miss" in any select. |---------+----------------------------> | | "Randy Chrismon" | | | <[EMAIL PROTECTED]| | | ia.net> | | | | | | 15/09/2003 16:00 | | | | |---------+----------------------------> >--------------------------------------------------------------------------- ---------------------------------------------------| | | | To: [EMAIL PROTECTED] | | cc: | | Subject: Does NULL == ""? | >--------------------------------------------------------------------------- ---------------------------------------------------| 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. Thanks. Randy -- 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] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
