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SQL DISTINCT shows 2 same results

Posted on 2009-07-07
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Last Modified: 2012-05-07
This SQL syntax shows 2 same results.
DISTINCT is not working.
What am I missing?

Thank you
SELECT DISTINCT C.CustomerID, C.FirstName, C.LastName,  C.Email, C.Password, C.Address, C.City, C.State, C.Country, C.Post, C.Phone, C.BestTimes, C.CreateDate, C.LastLogin, C.ContactPref, C.EstGiven, C.JobFini, C.Deposit, C.ActiveCust, C.CustNotes, B1.ImageID AS LatestImageID, B2.Comment AS LatestComment, B2.Poster, B2.PostDate AS Postdate FROM Customers AS C LEFT OUTER JOIN Employees AS E ON C.empID = E.empID LEFT OUTER JOIN (SELECT CustomerID, MAX(PostDate) AS MaxDate FROM blog WHERE (ImageID <> '') GROUP BY CustomerID) AS M1 ON M1.CustomerID = C.CustomerID LEFT OUTER JOIN blog AS B1 ON B1.CustomerID = M1.CustomerID AND B1.PostDate = M1.MaxDate LEFT OUTER JOIN (SELECT CustomerID, MAX(PostDate) AS MaxDate FROM blog AS blog_1 WHERE (Comment <> '') GROUP BY CustomerID) AS M2 ON M2.CustomerID = C.CustomerID LEFT OUTER JOIN blog AS B2 ON B2.CustomerID = M2.CustomerID AND B2.PostDate = M2.MaxDate WHERE (E.Username = @username) AND (C.ActiveCust = 1) ORDER BY C.LastLogin DESC

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Question by:jtuttle99
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9 Comments
 
LVL 59

Expert Comment

by:Kevin Cross
ID: 24799181
Are they exactly the same or is there one column that is different?

What is your SQL platform and version?
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Expert Comment

by:pssandhu
ID: 24799184
When you say 2 same results, do you mean all the columns listed in the sql are repeating or most of them but there are couple that have different value.
When you do a select distinct like above that means all the values in all the columns have to same in order to be grouped into one distinct record.
P.
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LVL 59

Expert Comment

by:Kevin Cross
ID: 24799208
In the interim, you can try it like this:
SELECT C.CustomerID, C.FirstName, C.LastName,  C.Email, C.Password

, C.Address, C.City, C.State, C.Country, C.Post

, C.Phone, C.BestTimes, C.CreateDate, C.LastLogin, C.ContactPref

, C.EstGiven, C.JobFini, C.Deposit, C.ActiveCust, C.CustNotes

, B1.ImageID AS LatestImageID, B2.Comment AS LatestComment, B2.Poster, B2.PostDate AS Postdate 

FROM Customers AS C 

LEFT OUTER JOIN Employees AS E ON C.empID = E.empID 

LEFT OUTER JOIN ((SELECT CustomerID, MAX(PostDate) AS MaxDate FROM blog WHERE (ImageID <> '') GROUP BY CustomerID) AS M1

	INNER JOIN blog AS B1 ON B1.CustomerID = M1.CustomerID AND B1.PostDate = M1.MaxDate) ON M1.CustomerID = C.CustomerID 

LEFT OUTER JOIN ((SELECT CustomerID, MAX(PostDate) AS MaxDate FROM blog AS blog_1 WHERE (Comment <> '') GROUP BY CustomerID) AS M2 

	INNER JOIN blog AS B2 ON B2.CustomerID = M2.CustomerID AND B2.PostDate = M2.MaxDate) ON M2.CustomerID = C.CustomerID 

WHERE (E.Username = @username) AND (C.ActiveCust = 1) 

ORDER BY C.LastLogin DESC

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Author Comment

by:jtuttle99
ID: 24799506
pssandhu:
Yes, some has duplicate results and some doesn't.
The duplucate results are exactly same results.
so looks like this

john
john
mark
brad
james
james
bob



mwvisa1:
I tried your code, but I got exactly same results (some duplicate displays)

Thank you
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Author Comment

by:jtuttle99
ID: 24799562
oh, I'm using SQL server 2008 express edition.
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LVL 59

Expert Comment

by:Kevin Cross
ID: 24799589
Can you display the full row of two of the duplicate records, please.  That will help construct query to filter them out.  One thought with SQL Server 2008 is to use ROW_NUMBER() function with an OVER analytical statement; however, would have to know the exact columns that make the row unique/duplicate.
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Author Comment

by:jtuttle99
ID: 24799639
Here is the screen shot. It's pretty long list, so I cut it half
screenshot.14.jpg
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Accepted Solution

by:
Kevin Cross earned 500 total points
ID: 24799662
CustomerID 3873 is the duplicate record in your picture from what I can see and it has two different LastLogin values, so you can see if this gets what you want.  If it does, then you may need to group by all the columns except for the LastLogin on which you will need to use an aggregate function like MAX or MIN.

The other records all had different data in random columns despite all having first name Shiny.  If that is what you are referring to as duplicates, then you will have to decide which is the valid one to keep as DISTINCT won't work there.
SELECT C.CustomerID, C.FirstName, C.LastName,  C.Email, C.Password

, C.Address, C.City, C.State, C.Country, C.Post

, C.Phone, C.BestTimes, C.CreateDate, /*C.LastLogin,*/ C.ContactPref

, C.EstGiven, C.JobFini, C.Deposit, C.ActiveCust, C.CustNotes

, B1.ImageID AS LatestImageID, B2.Comment AS LatestComment, B2.Poster, B2.PostDate AS Postdate 

FROM Customers AS C 

LEFT OUTER JOIN Employees AS E ON C.empID = E.empID 

LEFT OUTER JOIN ((SELECT CustomerID, MAX(PostDate) AS MaxDate FROM blog WHERE (ImageID <> '') GROUP BY CustomerID) AS M1

        INNER JOIN blog AS B1 ON B1.CustomerID = M1.CustomerID AND B1.PostDate = M1.MaxDate) ON M1.CustomerID = C.CustomerID 

LEFT OUTER JOIN ((SELECT CustomerID, MAX(PostDate) AS MaxDate FROM blog AS blog_1 WHERE (Comment <> '') GROUP BY CustomerID) AS M2 

        INNER JOIN blog AS B2 ON B2.CustomerID = M2.CustomerID AND B2.PostDate = M2.MaxDate) ON M2.CustomerID = C.CustomerID 

WHERE (E.Username = @username) AND (C.ActiveCust = 1) 

ORDER BY C.LastLogin DESC

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Author Comment

by:jtuttle99
ID: 24799855
Yes, it did work if I get rid of LastLogin.
Somehow, I got duplicate data in Customer table.
I have no idea when this happened, but I erased the table and imported again.

Thank you very much for your help!!!
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