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Home / Tricky Select Queries / Question No: 48

How to find duplicate records from a table in MySQL?

I have a table (employees) without a primary key. I want to make the emp_email_address field the primary key, only problem is, several records already share the same emp_email_address. How do I write a query which will show me all the instances where emp_ email_address is duplicated throughout the table.

Answer No: 48

Something like the following query should help you find all of the duplicate records:
SELECT emp_email_address FROM table GROUP BY emp_email_address HAVING COUNT(*)>1;

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