Primary key

[fizzwizz]

Error

SQL-query :

ALTER TABLE retailers DROP PRIMARY KEY ,
ADD PRIMARY KEY ( retnum )

MySQL said:

Duplicate entry '0' for key 1

Why cant i add this as primary key?

[barand]

My guess would be that you have two, or more, records which have a value of zero in field retnum.

The clue is in the error message. A primary key has to have unique values.

[fizzwizz]

I really must be having one of those days ... that was so obvious but I just didn't see it.

I added the field retnum as an afterthought and assumed there were no records (as it was new) ... but of course 0 was added as default

Thanks for that, .... much appreciated