Question

I want to move some data from one table to another. I wrote a query that I think will work, but in the destination table, there is a column that contains an id. I want each row I insert to have a different and consecutive id. Here is a simplificated example:

Table1
Name Telephone Actie
Peter 123456 Y
Michael 111111 Y
George 1234445 N

Table2
Id Name Likes
1 Peter Books
2 Michael Books

The query I wrote:

insert all into table2 (name, likes)
select all.name name, 'Books' likes, from (select o.name
  from table1 o where o.active='Y') all;

Is there any way of generating the consecutive ids and use the “insert all into” query? A sequence? If it can be made with a sequence… is there any way of doing it without a sequence?

Thanks and regards!

Answer 1

The proper way to generate id’s in Oracle is by using a sequence.

create sequence seq_table2_id nocache;

Then upon inserting call seq_table2_id.nextval.

insert into table2 (id, name, likes)
select seq_table2_id.nextval
,      o.name
,      'Books'
from   table1 o
where  o.active = 'Y'

Personally I use a trigger to automatically call the sequence on inserts, but there are people who dislike using triggers.