Re: [SQL] if else query help

[Jean-Christophe Boggio]

hi Brian,

BCD> I need to write a query that will pull information from table2 if 
BCD> information in table1 is older then xdate.

BCD> My laymen example:

BCD> SELECT table2.date, count(table2.name) as count
BCD> WHERE table1.startdate > 2 weeks
BCD> AND table2.submitdate > 2 weeks
BCD> ;

BCD> So i Guess my real questions is how do I determine the age of an entry to 
BCD> another table?

Try this :

Select table2.date,count(table2.name) as count
  from table1 as t1, table2 as t2
 where t1.itemid=t2.itemid -- to link the tables
   and t1.startdate>now()-14
   and t2.submitdate>now()-14;

Someone corrects me if I'm wrong, I come from the Oracle world...

Dates (or I should say TimeStamps) are stored as floating point values
: the integer part is the number of days since a certain date
(epoch or 01/01/1970 on unix-based databases) and the fractionnal part is the
portion of the day (although I don't know --yet-- how to convert
date2-date1 to an integer, trunc does not work).

HTH

--
Jean-Christophe Boggio
[EMAIL PROTECTED]
Independant Consultant and Developer
Delphi, Linux, Oracle, Perl

[SQL] Help with GROUP BY

[Jean-Christophe Boggio]

Hi,

I have a (quite) big table with ~3M rows.

Every row has a NBPOINTS (int4) and a REASON (int4)

select sum(nbpoints) from points;
  it takes about 10s

select sum(nbpoints) from points group by reason
  it takes about 210s

Same table structure, same data on Oracle gives respectively 8 and 22
seconds.

Is there a way to optimize this ?

(REASON is indexed though I can see no interest in this query.)

TIA!

--
Jean-Christophe Boggio
[EMAIL PROTECTED]
Independant Consultant and Developer
Delphi, Linux, Oracle, Perl

[SQL] Strange DISTINCT !

[Jean-Christophe Boggio]

Hello, can someone explain to me why this query is so slow :

select distinct t.idmembre,p.datecrea
from   tmp_stat t,prefs p
where  p.idmembre=t.idmembre
limit  5;

And this one is so fast :

select t.idmembre,p.datecrea
from   (select distinct idmembre from tmp_stat) as t,
   prefs p
where  p.idmembre=t.idmembre
limit 5;
 
(I currently have idmembre as an index on tmp_stat and prefs)

How does DISTINCT work ? Is this a bug or a misconfigured index ?

--
Jean-Christophe Boggio   
[EMAIL PROTECTED]   -o)
Independant Consultant and Developer /\\
Delphi, Linux, Perl, PostgreSQL _\_V


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