Herve,
> toto@aol.com
> tutu@aol.com
> toto@be.com
> tutu@be.com
> toto@yahoo.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
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 '
DECLAREemail_addr ALIAS for $1;mail_box CHAR(60);mail_domain CHAR(60);
BEGINmail_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;
END;'
LANGUAGE 'plpgsql';
Then:
SELECT user_id, email, email_sort(email) as sortcol
FROM users
ORDER BY sortcol;
However, this solution has a number of problems for data integrity down
the line. If e-mail addresses are that important to your application, I
greatly encourage you to split the field.
-Josh Berkus
P.S. Roberto, please add the above to our function library.
______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete
informationtechnology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small
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