Result Formatting and Aliases

SQL lets you rename columns or tables in your result using aliases. This makes your queries and output easier to read and understand, especially in reports or dashboards.

You can rename a column in your result using the AS keyword:

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SELECT AVG(order_total) AS average_order
FROM client_orders;

This shows the result as average_order instead of just avg.

You can also skip AS and write:

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SELECT AVG(order_total) average_order
FROM client_orders;

Both work — but AS makes it clearer.

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SELECT 
  region AS client_region,
  COUNT(*) AS total_clients,
  SUM(order_total) AS region_revenue
FROM clients
JOIN client_orders ON clients.id = client_orders.client_id
GROUP BY region;

This makes each part of the output more readable and well-labeled.

You can also rename tables using descriptive aliases, which is especially useful in complex queries involving multiple joins:

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SELECT client_data.name, order_data.order_total
FROM clients AS client_data
JOIN client_orders AS order_data ON client_data.id = order_data.client_id;

Aliases like client_data and order_data improve clarity, especially in longer or nested queries.