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Distinct with many columns - Continue

Posted on 2008-06-14
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Last Modified: 2010-04-21
I was too quick to accept the solution. If I do as suggested (see below). Then I only get value from s.Col1, but not from the 2 other columns. How can I get the value from all the columns?
Suggested solution:
Select s.Col1, Max(s.Col2), Max(t.Col3)
FROM TestTable t
JOIN SecondTable s
ON s.Col2=t.Col2
WHERE t.ProjectId=@ProjectId
GROUP BY s.Col1


I have a SPROC that I use to select from 3 columns. I want to get all columns returned, but only with distinct Col1 rows.  The sproc below does however not return distinct rows. What can I do?

The SPROC goes something like this:
Select DISTINCT s.Col1, s.Col2, t.Col3 FROM TestTable t
JOIN SecondTable s
ON s.Col2=t.Col2
WHERE t.ProjectId=@ProjectId

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Question by:johnkainn
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6 Comments
 
LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 21785211
you need to clarify, in case you have 2 or more rows for 1 value of Col1, which rows/values have to be returned? like "first/last" row (in which order?), max/min values etc ?
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Author Comment

by:johnkainn
ID: 21785329
How can I do that if Col1 is a text (nvarchar)? The other 2 columns are int.
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LVL 142

Expert Comment

by:Guy Hengel [angelIII / a3]
ID: 21785335
please show data samples of your data, and expected output, best with plain english explanation about the output.
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Author Comment

by:johnkainn
ID: 21785385
I leave out Col3 as it is not important for this case.
Table data:
Col1   Row1:   "Name1"     Row2: "Name2"    Row3:  "Name1"  
Col2:  Row1:      1              Row2: 2          Row3: 1
Output:
Row1:  a) "Name1"    b)  1
Row2:  b) "Name2"    b) 2
Col2 alway refers to Col1. It is its Id. I would only like to have each "Name" appear once in Output.
Thanks
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LVL 142

Accepted Solution

by:
Guy Hengel [angelIII / a3] earned 125 total points
ID: 21785425
if the col1 and col2 are always the same, then just GROUP BY the 2 values:

Select s.Col1, s.Col2, Max(t.Col3)
FROM TestTable t
JOIN SecondTable s
ON s.Col2=t.Col2
WHERE t.ProjectId=@ProjectId
GROUP BY s.Col1, s.col2

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Author Closing Comment

by:johnkainn
ID: 31467179
Thank you:-)
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