My Favorite SQL Formatter Style

Let’s take a well-written SQL query and break down the principles that make it effective.

Example: Well-Formatted SQL Query

				
					SELECT  
    customer_id,  
    first_name,  
    last_name,  
    SUM(order_total) AS total_spent  
FROM  
    customers c  
INNER JOIN  
    orders o  
    ON c.customer_id = o.customer_id  
WHERE  
    order_date >= '2024-01-01'  
    AND order_date <= '2024-12-31'  
GROUP BY  
    customer_id,  
    first_name,  
    last_name  
HAVING  
    SUM(order_total) > 500  
ORDER BY  
    total_spent DESC;

Key Features of This Style:

  • Keywords Capitalized and Aligned: SELECT, FROM, WHERE, and others are aligned vertically for clarity.
  • Logical Line Breaks: Each clause (WHERE, GROUP BY, etc.) is on its own line to isolate functionality.
  • Indented Columns and Conditions: Indentation is used to emphasize hierarchy and relationships.
  • Readable JOIN Conditions: The INNER JOIN and ON clause are visually linked.
Example 1: Inconsistent Indentation

Poorly formatted queries cause frustration and inefficiencies. Let’s look at some examples.

				
					SELECT customer_id, first_name,  
            last_name, SUM(order_total) AS total_spent  
    FROM customers c INNER JOIN  
        orders o ON c.customer_id = o.customer_id WHERE  
 order_date >= '2024-01-01'  
AND order_date <= '2024-12-31' GROUP BY customer_id,  
    first_name, last_name HAVING  
SUM(order_total) > 500  
 ORDER BY total_spent DESC;
Issues
  • No line breaks make the query difficult to read.
  • Logical sections blend into one another, complicating debugging.
Example 2: Misaligned Keywords and Conditions
				
					SELECT customer_id, first_name, last_name, 
SUM(order_total) AS total_spent
    FROM customers c
INNER JOIN orders o
ON c.customer_id = o.customer_id WHERE order_date >= '2024-01-01' 
AND order_date <= '2024-12-31'
        GROUP BY customer_id, first_name, last_name 
HAVING SUM(order_total) > 500 ORDER BY total_spent DESC;
Why it’s bad:
  • Keywords are not aligned, breaking the logical flow of the query.
  • The WHERE clause conditions run into each other without indentation, making them hard to scan.
  • Multi-line expressions like the SELECT clause lack consistent structure.

The Difference in Practice

				
					SELECT
    customer_id,
    first_name,
    last_name,
    SUM(order_total) AS total_spent
FROM
    customers c
INNER JOIN
    orders o
    ON c.customer_id = o.customer_id
WHERE
    order_date >= '2024-01-01'
    AND order_date <= '2024-12-31'
GROUP BY
    customer_id,
    first_name,
    last_name
HAVING
    SUM(order_total) > 500
ORDER BY
    total_spent DESC;

 In contrast to the poorly formatted examples, this style:

  • Highlights the logical structure of the query.
  • Makes debugging faster by isolating each clause.
  • Scales well to more complex queries with subqueries, unions, or additional filters.

Conclusion

SQL is more than just a query language—it’s a medium of communication among developers. Proper formatting transforms SQL from a jumble of text into clear, maintainable logic. By following principles like keyword alignment, logical line breaks, and consistent indentation, you can ensure your SQL is not only functional but elegant.

Do you have a favorite SQL formatting style? Or are you stuck with a colleague’s spaghetti-code queries? Share your thoughts in the Forum!