Re: Mysterious duplicate entry error for key from MySQL Backup

[Bill Swartz]

This may be out of context for Error #1062 occurring in a backup/restore, but there is another cause similar to the trigger cause mentioned earlier in this thread. If you are inserting into a table WITHOUT an auto-incremented primary key from a select (i.e. "INSERT table SELECT 1, ..."), if the select returns multiple rows the insert will fail with Err 1062 since the statement is trying to insert more than one identical primary key value ("1" in the parenthetical sample above). Hence the error text, "duplicate entry '1' for key 1".