Write a SQL query to find duplicate rows in a table.

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To find duplicate rows in a table, you can use the GROUP BY and HAVING clauses. The idea is to group the records by the columns that should be unique, and then filter groups that occur more than once.

✅ Generic SQL Query for Finding Duplicates

SELECT column1, column2, column3, COUNT(*) AS duplicate_count
FROM your_table
GROUP BY column1, column2, column3
HAVING COUNT(*) > 1;

🔎 Explanation

• column1, column2, column3: Replace these with the columns you want to check duplicates on.

• COUNT(*): Counts how many times each group of values occurs.

• HAVING COUNT(*) > 1: Ensures only duplicate groups (appearing more than once) are shown.

📌 Example

Suppose you have a table employees with columns name, email, and department. To find duplicate employees with the same email:

SELECT email, COUNT(*) AS duplicate_count
FROM employees
GROUP BY email
HAVING COUNT(*) > 1;

This will return all emails that appear more than once along with how many times they are duplicated.

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