Обсуждение: Number formatting

Hi,

Simple question, which is probably something obvious I'm missing.  If
anyone can tell me better how to do what I'm doing, go for it!

This is for a billing system, and I want PostgreSQL to generate unique
reference numbers for each invoice that is something more meaningful
than 1, 2, 3 etc.

So, what I'm trying to do is use a primary key to generate invoice
numbers such as "INV0000001", "INV0000002" etc.  Obviously a sequence
generates the increments, but when I try formatting it, it adds a space
at the beginning of the number.  Here's the "default value" for the
primary key field:

(('INV'::text ||
to_char((nextval('customer_customer_id_seq'::regclass))::integer,
'0000000'::text)))::character varying

However what I end up with is: "INV 0000012"

If I take the "INV" portion out, and simply try and format the sequence
generated, I still get the space added: " 0000013"

(to_char((nextval('customer_customer_id_seq'::regclass))::integer,
'0000000'::text))::character varying

The field is defined as a varchar(10), which allows the 3-digit "INV",
and 7 numeric digits.  I have tried defining it as char(10) but still
get the same.

This is on PostgreSQL 8.1.4, Windows XP.

Thanks

Andy

On Sat, Jun 10, 2006 at 07:15:02PM +0100, Andy Shellam wrote:
> So, what I'm trying to do is use a primary key to generate invoice
> numbers such as "INV0000001", "INV0000002" etc.  Obviously a sequence
> generates the increments, but when I try formatting it, it adds a space
> at the beginning of the number.

The FM modifier suppresses padding spaces.

http://www.postgresql.org/docs/8.1/interactive/functions-formatting.html#FUNCTIONS-FORMATTING-DATETIMEMOD-TABLE

test=> SELECT 'INV' || to_char(123, 'FM0000000');
  ?column?
------------
 INV0000123
(1 row)

--
Michael Fuhr

Perfect

Thanks Michael :-)

Andy

Michael Fuhr wrote:
> On Sat, Jun 10, 2006 at 07:15:02PM +0100, Andy Shellam wrote:
>> So, what I'm trying to do is use a primary key to generate invoice
>> numbers such as "INV0000001", "INV0000002" etc.  Obviously a sequence
>> generates the increments, but when I try formatting it, it adds a space
>> at the beginning of the number.
>
> The FM modifier suppresses padding spaces.
>
> http://www.postgresql.org/docs/8.1/interactive/functions-formatting.html#FUNCTIONS-FORMATTING-DATETIMEMOD-TABLE
>
> test=> SELECT 'INV' || to_char(123, 'FM0000000');
>   ?column?
> ------------
>  INV0000123
> (1 row)
>