Find and show rows in table with duplicate values in columns - SQL

Could you please provide an example of SQL, that will get table rows with duplicate values in the specific columns ?

15 Jan 2021 at 06:47 PM

Hi,

You can get rows with duplicate values in the specific columns, by using SELECT in combination with GROUP, HAVING and COUNT. The following examples are focused on column email_address.

To see the occurrence of email addresses in the column, you can use this SQL:

SELECT email_address, COUNT(*) FROM users GROUP BY email_address HAVING COUNT(*) > 1;

To find and show the rows with duplicate values in the column, you can use this SQL with nested query:

SELECT * FROM users WHERE email_address IN (SELECT email_address FROM users GROUP BY email_address HAVING COUNT(*) > 1);
The nested queries may take longer time to execute.

16 Jan 2021 at 03:14 PM

Tim

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