Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Hi,
If you want to SORT descending considering multiple column, you need to
spefify DESC after each column.
Default is ASC.
So, your present sorting is ASC, ASC and DESC
You can specify
1 DESC, 2 DESC, 3 DESC
HTH
Denis
- Original Message -
From: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, April 21, 2004 4:00 PM
Subject: [SQL] Order by MM DD in reverse chrono order trouble
Hello,
I am trying to select distinct dates and order them in the reverse
chronological order. Although the column type is TIMESTAMP, in this
case I want only , MM, and DD back.
I am using the following query, but it's not returning dates back in
the reverse chronological order:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date) DESC;
This is what the above query returns:
date_part | date_part | date_part
---+---+---
2004 | 2 | 6
2004 | 4 |20
(2 rows)
I am trying to get back something like this:
2004 4 20
2004 4 19
2004 2 6
...
My query is obviously wrong, but I can't see the mistake. I was
wondering if anyone else can see it. Just changing DESC to ASC, did
not work.
Thank you!
Otis
---(end of broadcast)---
TIP 2: you can get off all lists at once with the unregister command
(send unregister YourEmailAddressHere to [EMAIL PROTECTED])
---(end of broadcast)---
TIP 8: explain analyze is your friend
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 I am trying to select distinct dates and order them in the reverse chronological order. Although the column type is TIMESTAMP, in this case I want only , MM, and DD back. If you don't need them separated (which I suspect may be the case), you can do something like this: SELECT DISTINCT TO_CHAR(add_date,'-MM-DD') AS bb FROM tt ORDER BY bb DESC; - -- Greg Sabino Mullane [EMAIL PROTECTED] PGP Key: 0x14964AC8 200404240716 -BEGIN PGP SIGNATURE- iD8DBQFAikzOvJuQZxSWSsgRAgqbAKDC75SQd2aExYaniSJIzovOlVjvCACgyOAl Q2KMp3YGBkQwy5y4h9r/96A= =4idZ -END PGP SIGNATURE- ---(end of broadcast)--- TIP 2: you can get off all lists at once with the unregister command (send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Indeed, it seems that I get the same result for a similar query.
I'm running version 7.3.4 on a rh 9 server.
Also: is the function date_part a function you wrote yourself? I get an error stating
that the function date_part(Unknown,date) is not recognized.
It maybe not a solution to the actual problem but you could try this:
save the date and the time in two seperate fields. I use a similar construction for
convenience.
Regards,
Stijn.
Hello,
Hm, doesn't work for me:
[EMAIL PROTECTED] mydb= select distinct date_part('year', uu.add_date),
date_part('month', uu.add_date), date_part('day',
uu.add_date) from uus inner join ui on uus.user_id=ui.id
inner join
uu on ui.id=uu.user_id where uus.subscriber_user_id=1 order by
uu.add_date desc;
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear
in target
list
I have this version of PostgreSQL installed: postgresql-7.3.4-3.rhl9
Thanks,
Otis
--- Tom Lane [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] writes:
I'd love to be able to do that, but I cannot just ORDER BY
uu.add_date,
because I do not have uu.add_date in the SELECT part of the
statement.
Sure you can. Back around SQL89 there was a restriction that ORDER
BY
values had to appear in the SELECT list as well, but no modern
database
has such a restriction anymore ...
regards, tom lane
---(end of
broadcast)---
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faqs/FAQ.html
---(end of broadcast)---
TIP 8: explain analyze is your friend
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Hello,
Thank you for all your help, Stijn.
date_part is a standard PG function.
While not the most elegant, the DESC, DESC, DESC solution suggested the
other day works okay for me, so I think I'll use that for now.
Thanks again!
Otis
--- Stijn Vanroye [EMAIL PROTECTED] wrote:
Indeed, it seems that I get the same result for a similar query.
I'm running version 7.3.4 on a rh 9 server.
Also: is the function date_part a function you wrote yourself? I get
an error stating that the function date_part(Unknown,date) is not
recognized.
It maybe not a solution to the actual problem but you could try this:
save the date and the time in two seperate fields. I use a similar
construction for convenience.
Regards,
Stijn.
Hello,
Hm, doesn't work for me:
[EMAIL PROTECTED] mydb= select distinct date_part('year', uu.add_date),
date_part('month', uu.add_date), date_part('day',
uu.add_date) from uus inner join ui on uus.user_id=ui.id
inner join
uu on ui.id=uu.user_id where uus.subscriber_user_id=1 order by
uu.add_date desc;
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear
in target
list
I have this version of PostgreSQL installed:
postgresql-7.3.4-3.rhl9
Thanks,
Otis
--- Tom Lane [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] writes:
I'd love to be able to do that, but I cannot just ORDER BY
uu.add_date,
because I do not have uu.add_date in the SELECT part of the
statement.
Sure you can. Back around SQL89 there was a restriction that
ORDER
BY
values had to appear in the SELECT list as well, but no modern
database
has such a restriction anymore ...
regards, tom lane
---(end of
broadcast)---
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faqs/FAQ.html
---(end of broadcast)---
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Hello,
I'd love to be able to do that, but I cannot just ORDER BY uu.add_date,
because I do not have uu.add_date in the SELECT part of the statement.
The reason I don't have it there is because I need distinct MM DD
values back.
Is there a trick that I could use to make this more elegant?
Thanks,
Otis
--- Edmund Bacon [EMAIL PROTECTED] wrote:
Is there some reason you can't do this:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
uu.add_date DESC;
This might be faster, as you only have to sort on one field, and I
think it should give the desired results
[EMAIL PROTECTED] wrote:
Hello,
I am trying to select distinct dates and order them in the reverse
chronological order. Although the column type is TIMESTAMP, in this
case I want only , MM, and DD back.
I am using the following query, but it's not returning dates back in
the reverse chronological order:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date) DESC;
This is what the above query returns:
date_part | date_part | date_part
---+---+---
2004 | 2 | 6
2004 | 4 |20
(2 rows)
I am trying to get back something like this:
2004 4 20
2004 4 19
2004 2 6
...
My query is obviously wrong, but I can't see the mistake. I was
wondering if anyone else can see it. Just changing DESC to ASC, did
not work.
Thank you!
Otis
---(end of
broadcast)---
TIP 2: you can get off all lists at once with the unregister command
(send unregister YourEmailAddressHere to
[EMAIL PROTECTED])
--
Edmund Bacon [EMAIL PROTECTED]
---(end of broadcast)---
TIP 8: explain analyze is your friend
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Yes indeed, I seem to have misinterpreted that last one. My apologies.
The distinct solution I mentioned isn't going to solve it, you are absolutely right in
your example.
To get back on track:
You don't have to use a field in the select part of you query to be able to use it in
the order by clause. So using order by add_date should indeed work. Since it appears
that your add_date is a timestamp field (including time) it will order first on the
date part, and next on the time part.
E.g.:
2004-04-12 12:45:22
2004-04-12 09:55:25
2004-04-11 14:25:31
2004-04-11 11:11:25
Since you have a distinct only on the date parts of the timestamp this will make no
difference in the end result, it will still be sorted correctly on the date.
but I'm wondering if a GROUP BY wouldn't also be a good solution? like this:
---CODE
SELECT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
GROUP BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date);
---END CODE
That way you don't need the DISTINCT part. The disadvantage however is that all the
fields in the select must eighter be a part of the GROUP BY clause, or be used in an
aggregate function.
Anyways: just descide whatever solution fits best for your needs.
Regards,
Stijn.
Otis wrote:
Hello,
But will this work even with my add_date column, which is a TIMESTAMP
field? Values in this column contain hours, minutes,
seconds, etc., so
won't DISTINCT return multiple rows for add_dates that _are_ distinct,
but are on the same day.
For example:
2004 04 02 11:22:33.034
2004 04 02 22:33:44.055
Thanks,
Otis
--- Stijn Vanroye [EMAIL PROTECTED] wrote:
Hello,
I'd love to be able to do that, but I cannot just ORDER BY
uu.add_date,
because I do not have uu.add_date in the SELECT part of the
statement.
The reason I don't have it there is because I need
distinct MM
DD
values back.
Is there a trick that I could use to make this more elegant?
yes, you could use:
SELECT DISTINCT ON (field1, field2) field1, field3, FieldN
from table
Regards,
Stijn Vanroye
---(end of broadcast)---
TIP 2: you can get off all lists at once with the unregister command
(send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
[EMAIL PROTECTED] writes: I'd love to be able to do that, but I cannot just ORDER BY uu.add_date, because I do not have uu.add_date in the SELECT part of the statement. Sure you can. Back around SQL89 there was a restriction that ORDER BY values had to appear in the SELECT list as well, but no modern database has such a restriction anymore ... regards, tom lane ---(end of broadcast)--- TIP 8: explain analyze is your friend
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Hello,
Hm, doesn't work for me:
[EMAIL PROTECTED] mydb= select distinct date_part('year', uu.add_date),
date_part('month', uu.add_date), date_part('day',
uu.add_date) from uus inner join ui on uus.user_id=ui.id inner join
uu on ui.id=uu.user_id where uus.subscriber_user_id=1 order by
uu.add_date desc;
ERROR: For SELECT DISTINCT, ORDER BY expressions must appear in target
list
I have this version of PostgreSQL installed: postgresql-7.3.4-3.rhl9
Thanks,
Otis
--- Tom Lane [EMAIL PROTECTED] wrote:
[EMAIL PROTECTED] writes:
I'd love to be able to do that, but I cannot just ORDER BY
uu.add_date,
because I do not have uu.add_date in the SELECT part of the
statement.
Sure you can. Back around SQL89 there was a restriction that ORDER
BY
values had to appear in the SELECT list as well, but no modern
database
has such a restriction anymore ...
regards, tom lane
---(end of broadcast)---
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faqs/FAQ.html
[SQL] Order by YYYY MM DD in reverse chrono order trouble
Hello,
I am trying to select distinct dates and order them in the reverse
chronological order. Although the column type is TIMESTAMP, in this
case I want only , MM, and DD back.
I am using the following query, but it's not returning dates back in
the reverse chronological order:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date) DESC;
This is what the above query returns:
date_part | date_part | date_part
---+---+---
2004 | 2 | 6
2004 | 4 |20
(2 rows)
I am trying to get back something like this:
2004 4 20
2004 4 19
2004 2 6
...
My query is obviously wrong, but I can't see the mistake. I was
wondering if anyone else can see it. Just changing DESC to ASC, did
not work.
Thank you!
Otis
---(end of broadcast)---
TIP 2: you can get off all lists at once with the unregister command
(send unregister YourEmailAddressHere to [EMAIL PROTECTED])
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Hello,
I am trying to select distinct dates and order them in the reverse
chronological order. Although the column type is TIMESTAMP, in this
case I want only , MM, and DD back.
I am using the following query, but it's not returning dates back in
the reverse chronological order:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date) DESC;
This is what the above query returns:
date_part | date_part | date_part
---+---+---
2004 | 2 | 6
2004 | 4 |20
(2 rows)
I am trying to get back something like this:
2004 4 20
2004 4 19
2004 2 6
...
My query is obviously wrong, but I can't see the mistake. I was
wondering if anyone else can see it. Just changing DESC to ASC, did
not work.
Thank you!
Otis
What you could try to do in your order by clause is the following:
ORDER BY
date_part('year', uu.add_date) DESC,
date_part('month', uu.add_date) DESC,
date_part('day', uu.add_date) DESC;
That way you are sure each of the fields is sorted DESC. if you don't specify a
direction in your order by clause postgres will take ASC as the default. I think that
he does ASC,ASC,DESC instead. I'm not sure if he applies the DESC to all specified
fields in the order by if you declare it only once.
Regards,
Stijn Vanroye
---(end of broadcast)---
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Thank you and Denis ([EMAIL PROTECTED]) - that was it. I needed
explicit DESC for each ORDER BY criterium.
Otis
--- Stijn Vanroye [EMAIL PROTECTED] wrote:
Hello,
I am trying to select distinct dates and order them in the reverse
chronological order. Although the column type is TIMESTAMP, in
this
case I want only , MM, and DD back.
I am using the following query, but it's not returning dates back
in
the reverse chronological order:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date) DESC;
This is what the above query returns:
date_part | date_part | date_part
---+---+---
2004 | 2 | 6
2004 | 4 |20
(2 rows)
I am trying to get back something like this:
2004 4 20
2004 4 19
2004 2 6
...
My query is obviously wrong, but I can't see the mistake. I was
wondering if anyone else can see it. Just changing DESC to ASC,
did
not work.
Thank you!
Otis
What you could try to do in your order by clause is the following:
ORDER BY
date_part('year', uu.add_date) DESC,
date_part('month', uu.add_date) DESC,
date_part('day', uu.add_date) DESC;
That way you are sure each of the fields is sorted DESC. if you don't
specify a direction in your order by clause postgres will take ASC as
the default. I think that he does ASC,ASC,DESC instead. I'm not
sure if he applies the DESC to all specified fields in the order by
if you declare it only once.
Regards,
Stijn Vanroye
---(end of
broadcast)---
TIP 9: the planner will ignore your desire to choose an index scan if
your
joining column's datatypes do not match
---(end of broadcast)---
TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
Re: [SQL] Order by YYYY MM DD in reverse chrono order trouble
Is there some reason you can't do this:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
uu.add_date DESC;
This might be faster, as you only have to sort on one field, and I think it should give the desired results
[EMAIL PROTECTED] wrote:
Hello,
I am trying to select distinct dates and order them in the reverse
chronological order. Although the column type is TIMESTAMP, in this
case I want only , MM, and DD back.
I am using the following query, but it's not returning dates back in
the reverse chronological order:
SELECT DISTINCT
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date)
FROM uus INNER JOIN ui ON uus.user_id=ui.id INNER JOIN uu ON
ui.id=uu.user_id
WHERE uus.x_id=1
ORDER BY
date_part('year', uu.add_date), date_part('month', uu.add_date),
date_part('day', uu.add_date) DESC;
This is what the above query returns:
date_part | date_part | date_part
---+---+---
2004 | 2 | 6
2004 | 4 |20
(2 rows)
I am trying to get back something like this:
2004 4 20
2004 4 19
2004 2 6
...
My query is obviously wrong, but I can't see the mistake. I was
wondering if anyone else can see it. Just changing DESC to ASC, did
not work.
Thank you!
Otis
---(end of broadcast)---
TIP 2: you can get off all lists at once with the unregister command
(send unregister YourEmailAddressHere to [EMAIL PROTECTED])
--
Edmund Bacon [EMAIL PROTECTED]
---(end of broadcast)---
TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
