SQL PRACTICE: SQL SERVER - Duplicate Records

 Q3. How to select duplicate records from a table using SQL?


N.B: I am using the following:

Database -> MSSQL

SQL Dialect -> T-SQL

I have a table given below:

Table1. Employee Table

To find duplicate records from the table, we need to use a row_number function to uniquely identify each row. 

select Empid,

Name,

Salary,

ROW_NUMBER() over(partition by empid, Name, Salary order by empid) as Row_Num

from employee

                                                    Table2. Row_Number Function

If  you see the Row_Num column above, it  is uniquely identifying each row. Now, we need to fetch a duplicate records having Row_Num grater than one. 

Let's see the SQL query:

With cte as (select Empid,

Name,

Salary,

ROW_NUMBER() over(partition by empid, Name, Salary order by empid) as Row_Num

from employee)

select Empid,

Name,

Salary

from cte

where Row_Num > 1;

Table3. Duplicate Records

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