How do I get original record and duplicate of same record to show up from a query

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Lets say I have a table that has INDID, Name, Date_of_birth, Place_of_birth, Date_of_death, Place_of_death.

how can I get duplicate records and the original record that was matched?

example:

1 jon jones 1/20/1920 some place 12/20/2020 some place
99 jon jones 1/20/1920 some place 12/20/2020 some place

if I use row over partition being > 1 I will get the individual with ID number 99. But I want to see both records. I cant use >=1 then that will show all records.

WITH cte AS (
    SELECT 
        Name, 
        Date_of_birth, 
        Place_of_birth, 
        Date_of_death, 
        Place_of_death, 
        ROW_NUMBER() OVER (
            PARTITION BY Name, Date_of_birth, Place_of_birth, Date_of_death, Place_of_death
            ORDER BY Name) rownum
    FROM 
        t1
) 
SELECT 
  * 
FROM 
    cte 
WHERE 
    rownum > 1;

What I have tried:

I tried looking for duplicate match syntax for sql and nothing fruitful came from it.

Posted 22-May-21 19:40pm

Member 11856456

Updated 22-May-21 22:30pm

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OriginalGriff · Answer 1 · 2021-05-22T20:10:00

Try using a GROUP BY, and then JOIN those results to your original table.
Assume we have this table:

ID  FName   SName   Email
1   Joe     Smith   Joe@xxx.com                                       
2   Mike    Jones   Mike@xxx.com                                      
3   Joe     Smith   Joe@xxx.com                                       
4   Mike    Smith   Mike.S@xxx.com

If we use GROUP BY, We can add a count of the rows:

SQL

SELECT [FName]
      ,[SName]
      ,[Email]
      ,COUNT(*) AS Cnt
  FROM [Testing].[dbo].[MyTable]
  GROUP BY [FName]
          ,[SName]
          ,[Email]

FName   SName   Email           Cnt
Joe     Smith   Joe@xxx.com       2
Mike    Jones   Mike@xxx.com      1
Mike    Smith   Mike.S@xxx.com    1

SO it's simple to convert that to just give duplicates:

SQL

SELECT [FName]
      ,[SName]
      ,[Email]
  FROM [Testing].[dbo].[MyTable]
  GROUP BY [FName]
          ,[SName]
          ,[Email]
  HAVING COUNT(*) > 1

:

FName   SName   Email           
Joe     Smith   Joe@xxx.com

Now all you have to do is JOIN them back together to get the IDs:

SQL

SELECT a.* FROM Testing.dbo.MyTable a
JOIN (SELECT [FName]
            ,[SName]
            ,[Email]
        FROM [Testing].[dbo].[MyTable]
        GROUP BY [FName]
                ,[SName]
                ,[Email]
        HAVING COUNT(*) > 1) b
      ON     a.Email = b.Email
         AND a.FName = b.FName
         AND a.SName = b.SName

ID  FName   SName   Email
1   Joe     Smith   Joe@xxx.com                                      
3   Joe     Smith   Joe@xxx.com

Wendelius · Answer 2 · 2021-05-22T22:30:00

One variation is to use EXISTS clause. Consider the following example

SQL

SELECT *
FROM YourTable yt
WHERE EXISTS (SELECT 1
              FROM YourTable yt2
              WHERE yt2.IndId          != yt.IndId
              AND   yt2.Name           =  yt.Name
              AND   yt2.Date_of_birth  =  yt.Date_of_birth
              AND   yt2.Place_of_birth =  yt.Place_of_birth
              AND   yt2.Date_of_death  =  yt.Date_of_death
              AND   yt2.Place_of_death =  yt.Place_of_death)

How do I get original record and duplicate of same record to show up from a query

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