Zen and the Art of Writing SQL Query

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description

Writing a query is an art! Simplicity, focus, and practice is all it takes. Understand the logical processing of a query and discover the art of writing simple and efficient queries. It is a journey that starts with FROM and ends with ORDER BY!

Transcript of Zen and the Art of Writing SQL Query

SELECT C.customer_name, SUM(O.order_amount) AS total FROM Customers AS C JOIN Orders AS O ON C.customer_nbr = O.customer_nbr WHERE C.customer_name LIKE 'J%' AND O.order_date >= '20090101' AND O.order_date < '20100101' GROUP BY C.customer_name HAVING SUM(O.order_amount) > 10 ORDER BY total DESC;

SELECT C.customer_name, SUM(O.order_amount) AS total FROM Customers AS C JOIN Orders AS O ON C.customer_nbr = O.customer_nbr WHERE C.customer_name LIKE 'J%' AND O.order_date >= '20090101' AND O.order_date < '20100101' GROUP BY C.customer_name HAVING SUM(O.order_amount) > 10 ORDER BY total DESC;

SELECT C.customer_name, SUM(O.order_amount) AS total FROM Customers AS C JOIN Orders AS O ON C.customer_nbr = O.customer_nbr WHERE C.customer_name LIKE 'J%' AND O.order_date >= '20090101' AND O.order_date < '20100101' GROUP BY C.customer_name HAVING SUM(O.order_amount) > 10 ORDER BY total DESC;