Hi, Sergei! 04.02.2019, 23:34, "Sergei Golubchik" <serg@mariadb.org>:
Hi, Eugene!
On Feb 04, Eugene Kosov wrote:
> create table t1 (a int unique); > insert t1 values (NULL),(NULL),(NULL); > alter table t1 modify a int auto_increment;
create table t1 (a int not null, unique key a_key (a)) engine=innodb; insert into t1 values (19), (1), (100500); alter table t1 modify a int not null auto_increment,algorithm=instant; drop table t1;
You've missed the point. I wrote that in some cases ALTER TABLE has to generate auto-increment values. Try this example:
create table t1 (a int not null, index (a)); insert t1 values (0),(0),(0); alter table t1 modify a int auto_increment; select * from t1;
OK. That's a lot more stuff to do but it's mostly clear now.
Regards, Sergei Chief Architect MariaDB and security@mariadb.org
-- Eugene