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Tue, 18 Dec 2012 15:15:41 -0800 (PST)
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Date: Tue, 18 Dec 2012 15:15:41 -0800 (PST)
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Subject: question about varchar
From: Rui Li <rui.vapps@gmail.com>
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To: pgsql-general@postgresql.org

In postgresql, we can create column as =93varchar(n)=94 where n is the size=
 of the char, or we can just define column as =93varchar=94
rli=3D# CREATE TABLE test (v1 varchar(100), v2 varchar);
CREATE TABLE
rli=3D# \d test
             Table "public.test"
Column |          Type          | Modifiers
--------+------------------------+-----------
v1     | character varying(100) |
v2     | character varying      |

so my question is: why should we even declare character varying(n) in postg=
resql when there=92s an easier options to declaring character varying (with=
out n)=20
is there any performance different between it? or some other reason we shou=
ld use varchar(n) instead of just varchar?

thanks for any help