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Group by having count(*)

Author

Topic

JeffS23
Posting Yak Master

212 Posts

Posted - 2008-01-03 : 21:06:12

I would like to select data from a database using 'Select * " based on a value in a row (same column)being unique.

By that I mean that that data must not repeat again. Idealy I would like to set the number my self so rather then unique I could say
select the rows from the database only if the uniquevalue does not repeat more then x number of times.
eg
Value A
Value B
Value C
Value B
Value B
Value C

So if I wanted to set the uniquness to 1 then only row with Value A would be collected.
If I set the uniquenss to =<2 then I would get data from rows with value A and C so
3 rows returned.

I have this so far

SELECT *
FROM SingleS.mdb
GROUP BY Uniquevalue
HAVING count(*) = 1

khtan
In (Som, Ni, Yak)

17689 Posts

Posted - 2008-01-03 : 21:09:50

[code]
SELECT Uniquevalue
FROM SingleS.mdb
GROUP BY Uniquevalue
HAVING count(*) = 1
[/code]

KH
[spoiler]Time is always against us[/spoiler]

JeffS23
Posting Yak Master

212 Posts

Posted - 2008-01-03 : 21:28:18

Its close and does exactly what it says. However it does not return the whole row which is what i need.

is there a way to do this?

khtan
In (Som, Ni, Yak)

17689 Posts

Posted - 2008-01-03 : 21:42:00

[code]SELECT a.*
FROM SingleS.mdb a
INNER JOIN
(
SELECT Uniquevalue
FROM SingleS.mdb
GROUP BY Uniquevalue
HAVING COUNT(*) = 1
) u
ON a.Uniquevalue = u.Uniquevalue[/code]

KH
[spoiler]Time is always against us[/spoiler]

visakh16
Very Important crosS Applying yaK Herder

52326 Posts

Posted - 2008-01-04 : 08:48:17

[code]SELECT a.*
FROM SingleS.mdb t1
INNER JOIN
(
SELECT Uniquevalue
FROM SingleS.mdb
GROUP BY Uniquevalue
HAVING COUNT(*) <= n
) t2
ON t2.Uniquevalue = t1.Uniquevalue[/code]

here n will be uniqueness number set by user

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