在两个表上使用 INNER JOIN 时，如何让它返回表中的每一列，

Question

Table dbo.Ögon

Table dbo.CaseTable

I have imported a.csv file and created a table out of the.csv file. It contains two columns that matches columns/values of a another table. This.csv file contains 2245 rows which also is the amount of rows in table I created called dbo.Ögon

Down below is the INNER JOIN query I've written.

SELECT * FROM [dbo].[CaseTable] P
INNER JOIN [dbo].[Ögon] O
ON P.Personnummer = O.Pnr;

This returns a result of 9085 rows which's not the result i was lookin for.

But!

If I write the query this way instead.

SELECT DISTINCT Personnummer, Fotodatum
FROM [dbo].[CaseTable] P
INNER JOIN [dbo].[Ögon] O
ON P.Personnummer = O.Pnr;

I get the exact same rows as the.csv file or as in table dbo.Ögon but I also see two columns.

So. What i'm looking for as a result when running query, is to see every column instead of two columns with the amount of rows that I stated before.

To clarify. Im looking for a column called CaseKey which does not exist in table dbo.Ögon but exists in table dbo.CaseTable

Hence why im looking for a query that returns all columns so I can see column CaseKey.

Hope I didn't make this too confusing:)

Answer 1

You appear to have duplicates -- I am guessing in the ogon table. One method uses ROW_NUMBER() . If this interpretation is correct, you can use:

SELECT p.*, o.*
FROM [dbo].[CaseTable] p JOIN
     (SELECT o.*, 
             ROW_NUMBER() OVER (PARTITION BY o.Pnr, o.FotoDatum ORDER BY NEWID()) as seqnum
      FROM [dbo].[Ögon] o
     ) o
     ON p.Personnummer = o.Pnr AND seqnum = 1;

Note that you would normally have an ORDER BY in the ROW_NUMBER() to specify which row you want.