Hi, So I decided to try grouping by result by salary and not emp_no but I got a result showing me duplicate values for the emp_no I remember that PK are not supposed to have duplicate values in a column, so I am wondering why this is different. Thanks

Hi Oyindamola! Thanks for reaching out! In this case we have a composite primary key - it consists of more than 1 column. So, the idea is that the combination of columns should be unique, but some of the columns can have duplicates. I attach a screenshot. Hope this helps. Best, Tsvetelin

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Oyindamola Oluwapelumi Okesola

Last answered:

07 Dec 2022

Posted on:

05 Dec 2022

WHY DOES A PRIMARY KEY HAVE DUPLICATE VALUES

in SQL / HAVING

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Tsvetelin Tsonkov

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Posted on:

07 Dec 2022

WHY DOES A PRIMARY KEY HAVE DUPLICATE VALUES

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