Обсуждение: how to sort a birthday list ?

Hi !

there's a nice query for retrieving the people who have their birthday 
in the next n days: (taken from Joe Celko's SQL for Smarties, 1st Ed., 
p. 76)

SELECT *
FROM Persons
WHERE EXTRACT( YEAR FROM AGE(dateofbirth) ) < EXTRACT( YEAR FROM AGE( 
CURRENT_DATE+60, dateofbirth ) )

... but how do I sort the list ?

On Thu, 2002-06-20 at 13:55, Michael Agbaglo wrote:
> Hi !
>
> there's a nice query for retrieving the people who have their birthday
> in the next n days: (taken from Joe Celko's SQL for Smarties, 1st Ed.,
> p. 76)
>
> SELECT *
> FROM Persons
> WHERE EXTRACT( YEAR FROM AGE(dateofbirth) ) < EXTRACT( YEAR FROM AGE(
> CURRENT_DATE+60, dateofbirth ) )
>
> ... but how do I sort the list ?


How about:
ORDER BY dateofbirth

Michael,

> SELECT *
> FROM Persons
> WHERE EXTRACT( YEAR FROM AGE(dateofbirth) ) < EXTRACT( YEAR FROM AGE(
> CURRENT_DATE+60, dateofbirth ) )
>
> ... but how do I sort the list ?

Easy:

SELECT person_name, person_department,  EXTRACT( YEAR FROM AGE(dateofbirth) )
as their_age
FROM Persons
WHERE EXTRACT( YEAR FROM AGE(dateofbirth) ) < EXTRACT( YEAR FROM AGE(
CURRENT_DATE+60, dateofbirth ) )
ORDER BY their_age, person_name

As an example.





--
-Josh Berkus

Dear Josh,

if you sort by AGE then the order will be young -> old or vice versa. 
I'd like to have the list sorted as interval birthDAY, birthMONTH and 
DAY from NOW() and MONTH from NOW().

example:

22.06.64 Person-1
26.06.50 Person-2
01.08.69 Person-3
02.08.71 Person-4
...

of course you could sort by DOY but then you'll have a problem w/ the 
next year:

if it's let's say december and you select the list for the next 60 days,
persons having birthday in december will appear after persons having 
birthday in january.

I tried to use CASE WHEN... THEN in ORDER BY but it doesn't seem to work 
(syntax error at '')

M.



Josh Berkus wrote:

> Michael,
> 
> 
>>SELECT *
>>FROM Persons
>>WHERE EXTRACT( YEAR FROM AGE(dateofbirth) ) < EXTRACT( YEAR FROM AGE( 
>>CURRENT_DATE+60, dateofbirth ) )
>>
>>... but how do I sort the list ?
>>
> 
> Easy:
> 
> SELECT person_name, person_department,  EXTRACT( YEAR FROM AGE(dateofbirth) ) 
> as their_age
> FROM Persons
> WHERE EXTRACT( YEAR FROM AGE(dateofbirth) ) < EXTRACT( YEAR FROM AGE( 
> CURRENT_DATE+60, dateofbirth ) )
> ORDER BY their_age, person_name
> 
> As an example.
> 
> 
> 
> 
> 
> 

David Stanaway wrote:

> 
> How about:
> ORDER BY dateofbirth
> 
> 
> 

doesn't work: it's sorted by YEAR ...

On Fri, Jun 21, 2002 at 10:30:54 +0200, Michael Agbaglo <byteshifter@shifted-bytes.de> wrote:
> 
> of course you could sort by DOY but then you'll have a problem w/ the 
> next year:
> 
> if it's let's say december and you select the list for the next 60 days,
> persons having birthday in december will appear after persons having 
> birthday in january.
> 
> I tried to use CASE WHEN... THEN in ORDER BY but it doesn't seem to work 
> (syntax error at '')

You also need to worry about leap years. If a birthday is February 29
and there isn't one this year, what do you want to happen?

Bruno Wolff III wrote:
> 
> On Fri, Jun 21, 2002 at 10:30:54 +0200,
>   Michael Agbaglo <byteshifter@shifted-bytes.de> wrote:
> >
> > of course you could sort by DOY but then you'll have a problem w/ the
> > next year:
> >
> > if it's let's say december and you select the list for the next 60 days,
> > persons having birthday in december will appear after persons having
> > birthday in january.
> >
> > I tried to use CASE WHEN... THEN in ORDER BY but it doesn't seem to work
> > (syntax error at '')
> 
> You also need to worry about leap years. If a birthday is February 29
> and there isn't one this year, what do you want to happen?

You can create a little PL/pgSQL function like this:

CREATE FUNCTION next_birthday(date) RETURNS date AS '
DECLARE    p_dob       ALIAS FOR $1;   v_age       integer;   v_birthday  date;
BEGIN   -- First we get the age in years   v_age := EXTRACT (YEAR FROM CURRENT_DATE) -             EXTRACT (YEAR FROM
p_dob);
   -- We add that to the DOB to get this years birthday   v_birthday := p_dob + (v_age::text || '' years'')::interval;
   -- If that is in the past, we add another year   IF v_birthday < CURRENT_DATE THEN       v_birthday := v_birthday +
''1year''::interval;   END IF;
 
   RETURN v_birthday;
END;'
LANGUAGE plpgsql;

It just calculates the next birthday of a person relative from today.
Then query with

SELECT next_birthday(birthday), name   FROM person ORDER BY 1;


Jan

-- 

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