Re: column "id" is of type integer but expression is of type character

> There isn't one. That's not how SQL works. You need to know what columns
> your tables have.
>
> If you want to update the primary key just do something like:
>
> INSERT INTO t1 SELECT * FROM t2;
> UPDATE t1 SET id = DEFAULT;
>
> Although if you don't know what your columns are called I can't see how
> you can figure out that you have a single-column pkey with
> auto-incrementing default.

I know most column names.
Customer can add few columns to tables which are not known to me at design
time.

The command

 INSERT INTO t1 SELECT * FROM t2;

causes primary key violation since t2 is subset of t1 and thus has primary
key values which are already present in t1.
So update is not possible.
Only way I see is to generate script dynamically at runtime containing all
columns excluding id column:

INSERT INTO t1 ( c1, c2, ..., cn )
SELECT c1,c2,  ...., cn
FROM t2;

or

INSERT INTO t1 ( id, c1, c2, ..., cn )
SELECT DEFAULT, c1,c2,  ...., cn
FROM t2;

in this case id column is populated automatically from sequence.
This is very ugly solution since requires dynamic script creation from pg
metadata instead of writing simple query.

Andrus.