"order by" is not supported for "insert ... select"

When filling a table with "insert ... select ...", "order by" cannot be specified.

There is no method to copy a table sorted into another table (except using export/import). This would be useful to optimize performance for big tables, or to create identity values that are ascending (related to another column).

Example:

create table temp1 (
s varchar(10));

insert into temp1 values 'x','a','c','b','a';

create table temp2 (
i integer not null
generated always as identity
primary key,
s varchar(10));

insert into temp2 (s)
select s from temp1 order by s;

--> Error: "order by" is not allowed.

– trying to use "group by" instead of "oder by":

insert into temp2 (s)
select s from temp1 group by s;
select * from temp2;

--> "group by" did not sort the table.