R: How to check if 2 series of data are equal - Mailing list pgsql-general

From Paolo Saudin
Subject R: How to check if 2 series of data are equal
Date
Msg-id 007101c98d39$9381f630$ba85e290$@it
Whole thread Raw
In response to Re: How to check if 2 series of data are equal  (Adrian Klaver <aklaver@comcast.net>)
Responses Re: R: How to check if 2 series of data are equal
List pgsql-general
>-----Messaggio originale-----
>Da: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] Per conto di Adrian Klaver
>Inviato: giovedì 12 febbraio 2009 17.28
>A: pgsql-general@postgresql.org
>Cc: Paolo Saudin
>Oggetto: Re: [GENERAL] How to check if 2 series of data are equal

>On Thursday 12 February 2009 12:06:41 am Paolo Saudin wrote:
>> Hi,
>>
>> I have 14 tables filled with meteorological data, one record per parameter
>> per hour. The id field holds the parameter type (1=temperature, 2=humidity
>> ...) My problem is that for short periods (maybe one week, one month) there
>> are two stations with the same data, I mean the temperature of table1 is
>> equal to the humidity of table3. I need to discover those cases.

>Before I can start to answer this I need some clarification. How can temperature
>and humidity be the same data?

Can be the same data ( and it is ) because of errors in the remote stations configurations.
The Stations and parameters IDs were mixed up resulting in same data in different tables ...

>>
>> I could pick one record in the first station and then compare it with the
>> ones in the other tables for all the parameters at that particular date. If
>> two records are equals (it probably happens) I must then check the next one
>> in the timeserie. If the second record is equal too, then probably the two
>> series may be equals and I must raise an alert from my application. Is
>> there a better and faster way to perform such a check ?
>>
>> -- tables
>> CREATE TABLE table1
>> (
>>   fulldate timestamp,
>>   id smallint NOT NULL,
>>   meanvalue real
>> ) WITH (OIDS=FALSE);
>> --.....................
>> --.....................
>> CREATE TABLE table14
>> (
>>   fulldate timestamp,
>>   id smallint NOT NULL,
>>   meanvalue real
>> ) WITH (OIDS=FALSE);
>> --
>> -- inserts
>> insert into table1(select
>> ('2009-01-01'::timestamp + interval '1 hour' * s.a)::timestamp,
>> 1::smallint, round(cast(random() as numeric), 1)::real
>> from generate_series(0,1000) as s(a)
>> );
>> --
>> insert into table2(select
>> ('2009-01-01'::timestamp + interval '1 hour' * s.a)::timestamp,
>> 1::smallint, round(cast(random() as numeric), 1)::real
>> from generate_series(0,1000) as s(a)
>> );
>> --
>> -- same data as table 1 -- MUST BE FOUND BY THE CKECK ROUTINE
>> insert into table3(select fulldate, id, meanvalue from table1);
>>
>>
>> Thank in advance,
>> Paolo Saudin



>--
>Adrian Klaver
>aklaver@comcast.net

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