How to find duplicate records in SQL?

SQL
#1

Let’s see how can we find duplicate records using the group by:

Employee Table

emp_id emp_name salary dept_id manager_id
E1 Rahul 15000 D1 M1
E2 Manoj 15000 D1 M1
E3 James 55000 D2 M2
E4 Michael 25000 D2 M2
E5 Ali 20000 D10 M3
E6 Robin 35000 D10 M3

Example

The following SQL query selects the duplicate salary figure in the Employee table.

SELECT salary, COUNT(*) 
FROM Employee
GROUP BY salary
HAVING COUNT(*) > 1;

Output

salary count
15000 2

Code Runner

Copy the below query in the code runner to see the result

SELECT salary, COUNT(*) 
FROM Employee
GROUP BY salary
HAVING COUNT(*) > 1;