Re: Order by email address

Herve, Etc.

Ooops! A couple of misteaks in that last post:

> > toto(at)aol(dot)com
> > tutu(at)aol(dot)com
> > toto(at)be(dot)com
> > tutu(at)be(dot)com
> > toto(at)yahoo(dot)com
> >
> > Is it possible and how ?
>
> Given the relational rule of Atomicity (each discrete piece of
> information shall have its own column or row), the solution is for
> you
> to make "e-mail id" and "domain" seperate fields. Then you can sort:
>
> ORDER BY mailbox, domain

I meant:
ORDER BY domain, mailbox

>
> If this is a legacy database, and splitting the field is not an
> option
> for you due to exisiting applications/policy, then you'll need to
> write
> a custom sorting function:
>
> CREATE FUNCTION email_sort (VARCHAR)
> RETURNS CHAR(120) AS '
> DECLARE
> email_addr ALIAS for $1;
> mail_box CHAR(60);
> mail_domain CHAR(60);
> BEGIN
> mail_box := CAST(SUBSTR(email_addr, 1, (STRPOS(email_addr, ''@'', 1)
> -1)) AS CHAR(60));
> mail_domain := CAST(SUBSTR(email_addr, (STRPOS(email_addr, ''@'', 1)
> +
> 1), 60) AS CHAR(60));
> RETURN mail_box || mail_domain;

I meant:
RETURN mail_domain || mail_box;

> END;'
> LANGUAGE 'plpgsql';
>
> Then:
>
> SELECT user_id, email, email_sort(email) as sortcol
> FROM users
> ORDER BY sortcol;
>

-Josh

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