Hi Sergei!

2014-12-13 21:06 GMT-02:00 Sergei Golubchik <serg@mariadb.org>:
Depends on how many rows the table errorsX has.

If it has only one row, than this INSERT ... SELECT will insert a one
row with a different id. No error.

If it has more than one row, this INSERT ... SELECT will try to insert
more than one row, all with the same id value - there will be a
duplicate key error.

Regards,
Sergei


well, let me reformulate the query...
INSERT INTO errorsX (id) SELECT IFNULL(MAX(id),0)+1 FROM errorsX GROUP BY NULL;

considering only a single row result with always >0 not null values