Conditional selection of RowNum in SQL - sql

Question

I have written a query which returns me following data.
ID EmpFirstName EmpLastName RowNum
1 X Y 1
2 A B 1
3 A B 2
Now I want all records where RowNum is >1. For example, in this case I need 2 and 3 record in output.
If I put condition RowNum >1 then I will get only third record but I want 2 as well.

Answer 1

Assuming your query is this:
select ID, EmpFirstName, EmpLastName,
ROW_NUMBER() OVER (PARTITION BY EmpFirstName, EmpLastName ORDER BY ID) AS RowNum
FROM aTable
This is a classic query used to filter out any duplicate values.
In order effectively select all the records with the duplicate values I can suggest using the COUNT() window function:
;with a as (
select ID, EmpFirstName, EmpLastName,
ROW_NUMBER() OVER (PARTITION BY EmpFirstName, EmpLastName ORDER BY ID) AS RowNum,
COUNT(*) OVER (PARTITION BY EmpFirstName, EmpLastName) AS cnt
FROM aTable
)
SELECT * FROM a where cnt > 1
ORDER BY EmpFirstName, EmpLastName
To test it use this query:
drop table #tmp
CREATE table #tmp (ID int , EmpFirstName varchar(10) , EmpLastName varchar(10))
go
INSERT INTO #tmp VALUES
(1,'X','Y' )
,(2,'A','B')
,(3,'A','B')
,(4,'A','C')
,(5,'B','C')
,(6,'B','C')
;with a as (
select ID, EmpFirstName, EmpLastName,
ROW_NUMBER() OVER (PARTITION BY EmpFirstName, EmpLastName ORDER BY ID) AS RowNum,
COUNT(id) OVER (PARTITION BY EmpFirstName, EmpLastName) AS cnt
FROM #tmp
)
SELECT * FROM a where cnt > 1
ORDER BY EmpFirstName, EmpLastName
Result:
ID EmpFirstName EmpLastName RowNum cnt
----------- ------------ ----------- -------------------- -----------
2 A B 1 2
3 A B 2 2
5 B C 1 2
6 B C 2 2

Answer 2

I make sample data and use this query
CREATE table #tmp (ID int , EmpFirstName varchar(10) , EmpLastName varchar(10) ,RowNum int)
INSERT INTO #tmp VALUES
(1,'X','Y',1)
,(2,'A','B',1)
,(3,'A','B',2)
SELECT ID,EmpFirstName,EmpLastName,RowNum
FROM (
SELECT *
,ROW_NUMBER() OVER (ORDER BY ID) AS [NEWrownum]
FROM #tmp
) q
WHERE q.NEWrownum > 1

Answer 3

try this,
DECLARE #Result TABLE (ID INT, EmpFirstName VARCHAR(10), EmpLastName VARCHAR(10), RowNum INT)
INSERT INTO #Result
VALUES
(1, 'X', 'Y', 1)
,(2, 'A', 'B', 1)
,(3, 'A', 'B', 2)
SELECT r1.*
FROM #Result r1
INNER JOIN (SELECT * -- get duplicate records
FROM #Result
WHERE RowNum = 2
) as r2 ON r1.EmpFirstName = r2.EmpFirstName
AND r1.EmpLastName = r2.EmpLastName