I used an inner join and got the same answer. Why should we use subquery over a join? I am still new. Would there be a case of using a join and not getting the same answer.

Hi Linda! Thanks for reaching out. In most cases JOINs are faster than sub-queries and it is very rare for a sub-query to be faster. The good thing in sub-queries is that they are more readable than JOINs. So, it is up to your choice. There are cases where you can only use a subquery. These cases are: Subquery in FROM With a GROUP BY SELECT column_name_1, column_name_2 FROM ( SELECT column_name_1, SUM(value) AS value_name FROM table_name_1 GROUP BY column_name_1 ) AS s WHERE value < 1500; - Subquery Returning an Aggregate Value in a WHERE Clause Example: SELECT column_name FROM table_name_1 WHERE value < (SELECT AVG(value) FROM table_name_2); Hope this helps. Best, Tsvetelin

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Linda Dunn

Last answered:

16 Nov 2022

Posted on:

14 Nov 2022

Join vs subquery

in SQL / SQL Subqueries with IN nested inside WHERE

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Tsvetelin Tsonkov

Instructor

Posted on:

16 Nov 2022

Join vs subquery

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