Seems useful

Best Regards,
A.Sreedhar.


-----Original Message-----
From: Dennis Povshedny [mailto:[EMAIL PROTECTED] 
Sent: Tuesday, September 25, 2007 4:40 PM
To: sqlite-users@sqlite.org
Subject: RE: [sqlite] select COUNT (DISTINCT column1, column2) from table?

Hi Phani!

For your sample the following query will fit:

select COUNT (DISTINCT year*12+month) FROM m

If you take a look at
EXPLAIN select COUNT (DISTINCT year*12+month) FROM m you will see that
effectiveness is almost the same than in case of EXPLAIN select COUNT
(DISTINCT year) FROM m

and significantly better than in
SELECT COUNT(*) FROM ( SELECT COUNT(*) FROM m group by year,month);


If it is not a real sample and you have string data you may concatenate
or something like this.

Hope this helps.

Regards, Dennis


Xeepe Phone Solution Team
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-----Original Message-----
From: B V, Phanisekhar [mailto:[EMAIL PROTECTED] 
Sent: Tuesday, September 25, 2007 2:46 PM
To: sqlite-users@sqlite.org
Subject: RE: [sqlite] select COUNT (DISTINCT column1, column2) from
table?


Hi Simon,

Yeah, I thought of the query which u mentioned. But the problem is
overhead is too much.

I was wondering why SQL doesn't support something like:
        Select COUNT (DISTINCT year, month) FROM table 
when it supports:
        select COUNT (DISTINCT year) FROM table

Regards,
Phani

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