Today I was inserting data from a csv into a mysql database and spent about an hour running into a weird error where the first time I inserted the data into the table I would get an error Error Code: 1062. Duplicate entry '1' for key 'PRIMARY'. The error is related to NO_AUTO_VALUE_ON_ZERO which generates an auto incrementing primary key when you insert a primary key with a value of zero. When I inserted the data a second time the primary key would have been auto incremented beyond the max row count so the error would go away.
Pretty odd bug.