Re: Copy table structure

On Wed, 2003-10-08 at 14:31, Chris Boget wrote:
> noob alert.
>
> > SELECT * FROM oldtable WHERE false;
>
> What exactly is this doing? What is the 'WHERE false' doing for the
> query?

"WHERE false" ensures that no rows are selected. When combined with
SELECT INTO (as I believe the original message suggested) the end result
is to create a new table with the same columns as oldtable but with no
rows:

junk=# select * from xxx;
id | xx
----+--------
1 | ????????????
(1 row)

junk=# select * into zzz FROM xxx WHERE false;
SELECT
junk=# select * from zzz;
id | xx
----+----
(0 rows)

But note that the table structure is not exactly the same:

junk=# \d xxx
Table "public.xxx"
Column | Type | Modifiers
--------+---------+-----------------------------------------------------
id | integer | not null default nextval('public.xxx_id_seq'::text)
xx | text | not null
Indexes:
"xxx_pkey" primary key, btree (id)

junk=# \d zzz
Table "public.zzz"
Column | Type | Modifiers
--------+---------+-----------
id | integer |
xx | text |

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
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