How to copy structure and contents of a table, but with separate sequence?
I'm using the following code to do it:
CREATE TABLE t_mytable (LIKE mytable INCLUDING ALL);ALTER TABLE t_mytable ALTER id DROP DEFAULT;CREATE SEQUENCE t_mytable_id_seq;INSERT INTO t_mytable SELECT * FROM mytable;SELECT setval('t_mytable_id_seq', (SELECT max(id) FROM t_mytable), true);ALTER TABLE t_mytable ALTER id SET DEFAULT nextval('t_my_table_id_seq');ALTER SEQUENCE t_mytable_id_seq OWNED BY t_mytable.id;
Postgres 10 or later
Postgres 10 introduced
IDENTITY columns conforming to the SQL standard (with minor extensions). The ID column of your table would look something like:
id integer PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY
Syntax in the manual.
Using this instead of a traditional
serial column avoids your problem with sequences.
IDENTITY columns use exclusive, dedicated sequences automatically, even when the specification is copied with
LIKE. The manual:
Any identity specifications of copied column definitions will only becopied if
INCLUDING IDENTITYis specified. A new sequence is createdfor each identity column of the new table, separate from the sequencesassociated with the old table.
INCLUDING ALLis an abbreviated form of
INCLUDING DEFAULTS INCLUDING IDENTITY INCLUDING CONSTRAINTS INCLUDING INDEXES INCLUDING STORAGE INCLUDING COMMENTS.
The solution is simpler now:
CREATE TEMP TABLE t_mytable (LIKE mytable INCLUDING ALL);INSERT INTO t_mytable TABLE mytable;SELECT setval(pg_get_serial_sequence('t_mytable', 'id'), max(id)) FROM tbl;
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Original (old) answer
You can take the create script from a database dump or a GUI like pgAdmin (which reverse-engineers database object creation scripts), create an identical copy (with separate sequence for the
serial column), and then run:
INSERT INTO new_tblSELECT * FROM old_tbl;
The copy cannot be 100% identical if both tables reside in the same schema. Obviously, the table name has to be different. Index names would conflict, too. Retrieving serial numbers from the same sequence would probably not be in your best interest, either. So you have to (at least) adjust the names.
Placing the copy in a different schema avoids all of these conflicts. While you create a temporary table from a regular table like you demonstrated, that's automatically the case since temp tables reside in their own temporary schema.
Or look at Francisco's answer for DDL code to copy directly.