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Without Primary Key Select / Delete First or Last n Records from Sql Server Table

Introduction: In this article I am going to explain how to select or delete first or last 5 or 10 or any number of rows from table in SQL Server when there is no primary key or unique identity column to filter the records. Or we can say getting and deleting specified number of records from top or bottom of the table without having any unique identity column in the table.


Description: To delete specified number of records from table we need a unique column for example primary key column through which we can filter the first or last n number of records using TOP and ORDER BY clause as I have mention in my previous article SQL Query to Delete or Select First or Last n Records from Table

But what if there is no primary key column in the table? In such case we have to generate a unique value to each row of table using inbuilt Sql Function ROW_NUMBER() and then we can filter the records using Top and order by clause and perform select or delete operation on them as mention below.

Implementation: Let’s create a table and delete n number of records from first or last.

--Create a table using following script
 CREATE TABLE #tbBooks
(  
    BookName   VARCHAR(100),
    Author     VARCHAR(100),
    Publisher  VARCHAR(100),
    BookPrice  DECIMAL(10,2)
)

--Add some dummy data into the table
GO
INSERT INTO #tbBooks VALUES
('Asp.Net','Ajay','Rozy Publication',1200),
('C#.Net','Sahil','Jai Publication',1000),
('VB.Net','Nancy','Rozy Publication',970),
('MVC','Sahil','Amar Publication',1480),
('JAVA','Supreet','Sam Publication',850),
('PHP','Parvesh','Maya Publication',800),
('ORACLE','Sunny','Amar Publication',1110),
('MYSQL','Shaheed','Sam Publication',400),
('jQuery','Amit','Maya Publication',950)


 --Check inserted data
SELECT * FROM #tbBooks

BookName
Author
Publisher
BookPrice
Asp.Net
Ajay
Rozy Publication
1200.00
C#.Net
Sahil
Jai Publication
1000.00
VB.Net
Nancy
Rozy Publication
970.00
MVC
Sahil
Amar Publication
1480.00
JAVA
Supreet
Sam Publication
850.00
PHP
Parvesh
Maya Publication
800.00
ORACLE
Sunny
Amar Publication
1110.00
MYSQL
Shaheed
Sam Publication
400.00
jQuery
Amit
Maya Publication
950.00


--Select first five records
SELECT TOP 5 ROW_NUMBER() OVER (ORDER BY (SELECT 1)) RowNum, * FROM #tbBooks ORDER BY RowNum ASC

RowNum
BookName
Author
Publisher
BookPrice
1
Asp.Net
Ajay
Rozy Publication
1200.00
2
C#.Net
Sahil
Jai Publication
1000.00
3
VB.Net
Nancy
Rozy Publication
970.00
4
MVC
Sahil
Amar Publication
1480.00
5
JAVA
Supreet
Sam Publication
850.00


--Select last five records
SELECT TOP 5 ROW_NUMBER() OVER (ORDER BY (SELECT 1)) RowNum, * FROM #tbBooks ORDER BY RowNum DESC

RowNum
BookName
Author
Publisher
BookPrice
9
jQuery
Amit
Maya Publication
950.00
8
MYSQL
Shaheed
Sam Publication
400.00
7
ORACEL
Sunny
Amar Publication
1110.00
6
PHP
Parvesh
Maya Publication
800.00
5
JAVA
Supreet
Sam Publication
850.00

--Select first 2 records from table and delete
;WITH CTE AS
(
SELECT TOP 2 ROW_NUMBER() OVER (ORDER BY (SELECT 1)) RowNum, * FROM #tbBooks ORDER BY RowNum ASC
)
DELETE FROM CTE

--Check data after deletion
SELECT * FROM #tbBooks

BookName
Author
Publisher
BookPrice
VB.Net
Nancy
Rozy Publication
970.00
MVC
Sahil
Amar Publication
1480.00
JAVA
Supreet
Sam Publication
850.00
PHP
Parvesh
Maya Publication
800.00
ORACEL
Sunny
Amar Publication
1110.00
MYSQL
Shaheed
Sam Publication
400.00
jQuery
Amit
Maya Publication
950.00

--Select last 2 records from table and delete
;WITH CTE AS
(
SELECT TOP 2 ROW_NUMBER() OVER (ORDER BY (SELECT 1)) RowNum, * FROM #tbBooks ORDER BY RowNum DESC
)
DELETE FROM CTE

--Check data after deletion
SELECT * FROM #tbBooks

BookName
Author
Publisher
BookPrice
VB.Net
Nancy
Rozy Publication
970.00
MVC
Sahil
Amar Publication
1480.00
JAVA
Supreet
Sam Publication
850.00
PHP
Parvesh
Maya Publication
800.00
ORACEL
Sunny
Amar Publication
1110.00

 Now over to you:
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