Get Second duplicate Record - sql

Question

I am getting after doing joins as ::
CompanyID EmpID Emp_no Location
-------------------- -------------------- ------------- -------------
1 24 100543 First.png
1 24 100543 Second.png
I want to select second Record i.e. Second.png by using CASE WHEN in select query.

Answer 1

Check this out.
declare #t table(CompanyID int, empid int, emp_no varchar(50), location varchar(100))
insert into #t values (1,24,100543,'First.png'),(1,24,100543,'Second.png'),(1,25,100544,'Second.png'),(1,25,100544,'First.png')
select * from
(
select
ROW_NUMBER() over(partition by companyid, empid order by companyid, empid ) rowno, *
from
#t
) a where rowno = 2 --and empid = 24 --here you can give empid to get particular employee detail
In case you want to get multiple empid's second entry in single select statement.
declare #t table(CompanyID int, empid int, emp_no varchar(50), location varchar(100))
insert into #t values (1,24,100543,'First.png'),(1,24,100543,'Second.png'),(1,25,100544,'Second.png'),(1,25,100544,'First.png')
,(1,26,100545,'First.png')
;with cte as
(
select
*
from
(
select
ROW_NUMBER() over(partition by empid order by empid ) rowno, *
from
#t
) a
),
cte1 as (
select
*,
ROW_NUMBER() OVER(PARTITION BY empid ORDER BY rowno DESC) as RN
from cte
)
select * from cte1 where rn = 1

Answer 2

You can write as:
;WITH CTE as
(
SELECT ROW_NUMBER() OVER ( PARTITION BY CompanyID,EmpID,Emp_no ORDER BY (SELECT 1))
AS rownum,CompanyID,EmpID,Emp_no,Location
FROM (SELECT * FROM #Test ) AS T
),CTE1 as
(
SELECT MAX(rownum) AS maxrownum,
CompanyID,
EmpID,
Emp_no
FROM CTE
GROUP BY CompanyID,EmpID,Emp_no
)
SELECT T.CompanyID,T.EmpID,T.Emp_no,T.Location
FROM CTE T
JOIN CTE1 T1 ON T.CompanyID = T1.CompanyID
AND T.EmpID = T1.EmpID
AND T.Emp_no = T1.Emp_no
AND T.rownum = T1.maxrownum
Explanation:
As there's no column like primary key through which we can identify
which row comes first you can write SELECT 1 in partition window.
Once you get rownumber for each combination of CompanyID,EmpID and Emp_no you can use second CTE to get the maxrow for each
combination
Just collect the data from the table for all rows with maxrownumbers
Hope this helps:)