This is a feature - a NULL value is an undefined value, therefore two NULL values are not the same. Can be a little confusing but makes sense when you think about it.
A UNIQUE index does ensure that non-NULL values are unique; you could specify that your column not accept NULL values. Dan On 12/11/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
Hi, I have an InnoDB table similar to this: CREATE TABLE Target (IMSI VARCHAR(15) ASCII, IMEI VARCHAR(15) ASCII, UNIQUE KEY (IMSI, IMEI)); After playing a bit with it, I managed to add duplicate records, if one of the fields was a NULL: +-----------------+-----------------+ | IMSI | IMEI | +-----------------+-----------------+ | NULL | 35195600126418 | | NULL | 35195600126418 | +-----------------+-----------------+ Is this a bug, or a feature? :-) If it is a feature, than how can I assure uniqueness for a table in a sense that won't allow such duplicates? Thx ImRe -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
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