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Thread: Fw: Count rows group by time intervals

Fw: Count rows group by time intervals

From
"Oliveiros Cristina"
Date:
Parents missing, sorry :-)
 
SELECT  a."date",a."theme",a.receiver,COUNT(*)
FROM table a
INNER JOIN table b
ON a."theme" = b."theme" AND a.receiver = b.receiver
WHERE (((b."date" - a."date") = 1) OR ((b."date" - a."date") = 0))
GROUP BY a."date",a."theme",a.receiver
HAVING (a."date" - '2007-01-01' ) % 2 = 0
ORDER BY a."date"
----- Original Message -----
Sent: Wednesday, May 09, 2007 2:44 PM
Subject: Re: [NOVICE] Count rows group by time intervals

Howdy, Loredana.
 
You need a query that returns the number of receivers on each theme, in two days intervals, is this correct?
 
Please try something like this. I am not sure if it works, because I don't have a table like yours.
I am assuming  your  table is called table
 
SELECT  a."date",a."theme",a.receiver,COUNT(*)
FROM table a
INNER JOIN table b
ON a."theme" = b."theme" AND a.receiver = b.receiver
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)
GROUP BY a."date",a."theme",a.receiver
HAVING (a."date" - '2007-01-01' ) % 2 = 0
ORDER BY a."date"
 
 
Then tell me if it worked
 
Cheers,
Oliveiros
 
----- Original Message -----
Sent: Wednesday, May 09, 2007 1:07 PM
Subject: [NOVICE] Count rows group by time intervals

Dear all,

I have the following table:

theme |   receiver        |           date
---------+----------------------+------------------------
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-27 00:00:00+00
 LIA   | +40741775622 |  2007-04-26 00:00:00+00
 LIA   | +40741775622 |  2007-04-26 00:00:00+00
 LIA   | +40741775622 |  2007-04-26 00:00:00+00
 LIA   | +40741775622 |  2007-04-26 00:00:00+00
 LIA   | +40741775622 |  2007-04-26 00:00:00+00
 LIA   | +40741775622 |  2007-04-25 00:00:00+00
 LIA   | +40741775622 |  2007-04-25 00:00:00+00
 LIA   | +40741775622 |  2007-04-25 00:00:00+00
 LIA   | +40741775622 |  2007-04-25 00:00:00+00
 LIA   | +40741775622 |  2007-04-25 00:00:00+00
 MIA   | +40741775622 | 2007-04-27 00:00:00+00
 MIA   | +40741775622 | 2007-04-27 00:00:00+00
 MIA   | +40741775622 | 2007-04-27 00:00:00+00
 MIA   | +40741775622 | 2007-04-27 00:00:00+00
 MIA   | +40741775622 |  2007-04-27 00:00:00+00
 MIA   | +40741775622 |  2007-05-09 00:00:00+00

I would like to count rows group by theme, receiver, and time intervals of
two days. I don't know how to start.

Hope that somebody could help me.




Re: Fw: Count rows group by time intervals

From
"Loredana Curugiu"
Date:
 
You need a query that returns the number of receivers on each theme, in two days intervals, is this correct?

yes, this is correct. Actually the interval in days is variable ( it would specified using PreparedStatemtent ).
Sorry I didn't say from the begining.

Please try something like this. I am not sure if it works, because I don't have a table like yours.
I am assuming  your  table is called table
 
SELECT  a."date",a."theme",a.receiver,COUNT(*)
FROM table a
INNER JOIN table b
ON a."theme" = b."theme" AND a.receiver = b.receiver
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)
GROUP BY a."date",a."theme",a.receiver
HAVING (a."date" - '2007-01-01' ) % 2 = 0
ORDER BY a."date"

The query above it's not working, I've got the following error:
     ERROR:  operator does not exist: interval % integer
     HINT:  No operator matches the given name and argument type(s). You may need to add explicit type casts.



Re: Fw: Count rows group by time intervals

From
"Oliveiros Cristina"
Date:
Funny thing.
In mine, it works...
On mine, If I subtract one date  from the other I get the number of days in between...which is another integer, I guess. and '%'  is the modular operator. Doesnt it work like this on yours?

Which version are you using?

try

SELECT (date - '2007-01-01') % 2
FROM table

to see if you get zeroes and ones .

Cheers,
Oliveiros

2007/5/9, Loredana Curugiu <loredana.curugiu@gmail.com >:
 
You need a query that returns the number of receivers on each theme, in two days intervals, is this correct?

yes, this is correct. Actually the interval in days is variable ( it would specified using PreparedStatemtent ).
Sorry I didn't say from the begining.

Please try something like this. I am not sure if it works, because I don't have a table like yours.
I am assuming  your  table is called table
 
SELECT  a."date",a."theme",a.receiver,COUNT(*)
FROM table a
INNER JOIN table b
ON a."theme" = b."theme" AND a.receiver = b.receiver
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)
GROUP BY a."date",a."theme",a.receiver
HAVING (a."date" - '2007-01-01' ) % 2 = 0
ORDER BY a."date"

The query above it's not working, I've got the following error:
     ERROR:  operator does not exist: interval % integer
     HINT:  No operator matches the given name and argument type(s). You may need to add explicit type casts.




Re: Fw: Count rows group by time intervals

From
"Loredana Curugiu"
Date:

Funny thing.
In mine, it works...
On mine, If I subtract one date  from the other I get the number of days in between...which is another integer, I guess. and '%'  is the modular operator. Doesnt it work like this on yours?

 
If I substract one date from the other I get an interval.

Which version are you using?

I am using 7.4.12 version of postgres.

try

SELECT (date - '2007-01-01') % 2
FROM table

to see if you get zeroes and ones . 

It's not working. I've got the same error.


Re: Fw: Count rows group by time intervals

From
"Loredana Curugiu"
Date:
If I use
 SELECT date_part( date-'2007-01-01' )::int % 2
 FROM table
I get zeros and ones.


Re: Fw: Count rows group by time intervals

From
"Oliveiros Cristina"
Date:
Ops... Mine is 8.2 beta 3...
With High probability the problem is difference in versions...
 
Well, Loredana, I have to say that Ive never used your version, so probably I cannot be a big help, then.
 
But you seem to know how to convert intervals to integers with the datepart()::int thing.
 
then Please try to enhance my query adding that to the three parts where I use date differences
 
Best,
 
Oliveiros
----- Original Message -----
Sent: Wednesday, May 09, 2007 4:01 PM
Subject: Re: Fw: [NOVICE] Count rows group by time intervals


Funny thing.
In mine, it works...
On mine, If I subtract one date  from the other I get the number of days in between...which is another integer, I guess. and '%'  is the modular operator. Doesnt it work like this on yours?

 
If I substract one date from the other I get an interval.

Which version are you using?

I am using 7.4.12 version of postgres.

try

SELECT (date - '2007-01-01') % 2
FROM table

to see if you get zeroes and ones . 

It's not working. I've got the same error.


Re: Fw: Count rows group by time intervals

From
Tom Lane
Date:
"Loredana Curugiu" <loredana.curugiu@gmail.com> writes:
>> On mine, If I subtract one date  from the other I get the number of days
>> in between...which is another integer, I guess. and '%'  is the modular
>> operator. Doesnt it work like this on yours?

> If I substract one date from the other I get an interval.

If you subtract two *date* values you get an integer.  If you subtract
two *timestamp* values you get an interval.

            regards, tom lane

Re: Fw: Count rows group by time intervals

From
"Loredana Curugiu"
Date:
Hi Oliveiros,

With your query I get the following result

          date                    | theme  |      receiver     | count
------------------------------------+----------+----------------------+-------
 2007-04-27 00:00:00+00 | MIA    | +40741775621 |    25
 2007-04-25 00:00:00+00 | LIA     | +40741775621 |    50
 2007-05-09 00:00:00+00 | MIA    | +40741775621 |     1
 2007-04-27 00:00:00+00 | LIA     | +40741775621 |    81

The count it is not correct.

Best,
      Loredana

Re: Fw: Count rows group by time intervals

From
"Oliveiros Cristina"
Date:
Yes,I've already figured out the mistake.
Can you please try this one?
Please Tell me if it worked
 
 
SELECT   a."date",a."theme",a.receiver,COUNT(*)
FROM (SELECT DISTINCT * FROM t_loredana) a
INNER JOIN t_loredana b
ON a."theme" = b."theme" AND a.receiver = b.receiver
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)
GROUP BY a."date",a."theme",a.receiver
HAVING (a."date" - '2007-01-01' ) % 2 = 0
ORDER BY a."date"
----- Original Message -----
Sent: Thursday, May 10, 2007 8:15 AM
Subject: Re: Fw: [NOVICE] Count rows group by time intervals

Hi Oliveiros,

With your query I get the following result

          date                    | theme  |      receiver     | count
------------------------------------+----------+----------------------+-------
 2007-04-27 00:00:00+00 | MIA    | +40741775621 |    25
 2007-04-25 00:00:00+00 | LIA     | +40741775621 |    50
 2007-05-09 00:00:00+00 | MIA    | +40741775621 |     1
 2007-04-27 00:00:00+00 | LIA     | +40741775621 |    81

The count it is not correct.

Best,
      Loredana

Re: Fw: Count rows group by time intervals

From
"Loredana Curugiu"
Date:
On 5/10/07, Oliveiros Cristina <oliveiros.cristina@marktest.pt> wrote:
Yes,I've already figured out the mistake.
Can you please try this one?
Please Tell me if it worked


I worked! Thanks a lot, Oliveiros.

I didn't understand which is the aim of the condition
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)

And should I modify the query if the time interval ( in days ) is varing?



Loredana


Re: Fw: Count rows group by time intervals

From
"Oliveiros Cristina"
Date:
Hello, Loredana.
 
Great to hear about the progress!!
 
Well, that part of the condition is to select the day, or the day after.
 
with the condition  ((a."date" - '2007-01-01' ) % 2 = 0 you obtain just the
even days, correct?
 
Then with the WHERE clause you are selecting, for a certain even day, all the records that match that day and the day after,  got the idea?
 
Then all you have to do it is COUNT them.
 
If it is to allow the time interval to vary, say you have a number of days of x.
 
Then you should change the HAVING clause to ((a."date" - '2007-01-01' ) % x = 0 ,
and change the WHERE clause to something like WHERE (((b."date" - a."date") >= 0) OR (b."date" - a."date") < x)
 
Try this, and please let me know if it solved the problem.
 
I use C# to access postgres database and it is very easy to parameterize a query with the NpgsqlParameter class.
 
I don't know if you are also using C# to interface with your database....
 
Take care
 
La revedere ,
 
Oliveiros :-)

 
----- Original Message -----
Sent: Thursday, May 10, 2007 12:40 PM
Subject: Re: Fw: [NOVICE] Count rows group by time intervals

On 5/10/07, Oliveiros Cristina <oliveiros.cristina@marktest.pt> wrote:
Yes,I've already figured out the mistake.
Can you please try this one?
Please Tell me if it worked


I worked! Thanks a lot, Oliveiros.

I didn't understand which is the aim of the condition
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)

And should I modify the query if the time interval ( in days ) is varing?



Loredana


Re: Fw: Count rows group by time intervals

From
"Oliveiros Cristina"
Date:
Hello  again, Loredana.
 
False alarm!
 
Sorry, the query we have is not the perfect version yet. It worked because (by luck) you have  even days for all intervals, but if you change the 9/5 day to 10/5 it would fail.
 
I am very sorry for having mislead you.
 
OK, then please substitute (SELECT DISTINCT * FROM t_loredana)
by
(SELECT DISTINCT  theme,receiver, (DATE'2007-01-01' + 2 *((date - '2007-01-01') / 2)) as date  FROM t_loredana)
 
and please eliminate the HAVING clause
 
So final result should be :
 
SELECT   a."date",a."theme",a.receiver,COUNT(*)
FROM (
SELECT DISTINCT  theme,receiver, (DATE'2007-01-01' + 2 *((date - '2007-01-01') / 2)) as date  FROM t_loredana
) a
INNER JOIN t_loredana b
ON a."theme" = b."theme" AND a.receiver = b.receiver
 WHERE (((b."date" - a."date") < 2) AND ((b."date" - a."date") >= 0) )
GROUP BY a."date",a."theme",a.receiver
 
ORDER BY a."date" 
 
Here 2 is the length of interval, the x I talked about on previous query.
 
You can substitute it by the length in days of the interval you want.
 
So to obtain 3 days interval it would become
 
 
SELECT   a."date",a."theme",a.receiver,COUNT(*)
FROM (
SELECT DISTINCT  theme,receiver, (DATE'2007-01-01' + 3 *((date - '2007-01-01') / 3)) as date  FROM t_loredana
) a
INNER JOIN t_loredana b
ON a."theme" = b."theme" AND a.receiver = b.receiver
WHERE (((b."date" - a."date") < 3) AND ((b."date" - a."date") >= 0) )
GROUP BY a."date",a."theme",a.receiver
ORDER BY a."date" 
 
The date column will have the first day of the 3 intervals where there are records, since 2007-01-01
 
Hope I got it right this time...
 
La revedere,
 
Oliveiros
----- Original Message -----
Sent: Thursday, May 10, 2007 2:37 PM
Subject: Re: Fw: [NOVICE] Count rows group by time intervals

Hello, Loredana.
 
Great to hear about the progress!!
 
Well, that part of the condition is to select the day, or the day after.
 
with the condition  ((a."date" - '2007-01-01' ) % 2 = 0 you obtain just the
even days, correct?
 
Then with the WHERE clause you are selecting, for a certain even day, all the records that match that day and the day after,  got the idea?
 
Then all you have to do it is COUNT them.
 
If it is to allow the time interval to vary, say you have a number of days of x.
 
Then you should change the HAVING clause to ((a."date" - '2007-01-01' ) % x = 0 ,
and change the WHERE clause to something like WHERE (((b."date" - a."date") >= 0) OR (b."date" - a."date") < x)
 
Try this, and please let me know if it solved the problem.
 
I use C# to access postgres database and it is very easy to parameterize a query with the NpgsqlParameter class.
 
I don't know if you are also using C# to interface with your database....
 
Take care
 
La revedere ,
 
Oliveiros :-)

 
----- Original Message -----
Sent: Thursday, May 10, 2007 12:40 PM
Subject: Re: Fw: [NOVICE] Count rows group by time intervals

On 5/10/07, Oliveiros Cristina <oliveiros.cristina@marktest.pt> wrote:
Yes,I've already figured out the mistake.
Can you please try this one?
Please Tell me if it worked


I worked! Thanks a lot, Oliveiros.

I didn't understand which is the aim of the condition
WHERE (((b."date" - a."date") = 1) OR (b."date" - a."date") = 0)

And should I modify the query if the time interval ( in days ) is varing?



Loredana


Re: Fw: Count rows group by time intervals

From
"Loredana Curugiu"
Date:
Hi, Oliveiros

Sorry for the delay. I wasn't on my desk on Friday, I took a short vacation :)
Your last solution is good, it solved my problem. The values for count are correct
now.

Your help and  explanations are very precious for me. Thank you very much.

Pe curand,
      Loredana