📈 SQL MIN and MAX – Find Minimum and Maximum Values

🧲 Introduction – What are MIN and MAX in SQL?

The MIN() and MAX() functions in SQL are used to retrieve the lowest and highest values in a column. These are powerful tools when analyzing data trends, identifying outliers, or setting boundaries for queries and reports.

🎯 In this guide, you’ll learn how to:

• Use MIN() and MAX() on numeric, date, and text columns
• Combine with GROUP BY and HAVING
• Handle NULL values appropriately

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✅ 1. Basic Syntax for MIN and MAX

SELECT MIN(column_name), MAX(column_name)
FROM table_name;

✅ Retrieves the smallest and largest values from the specified column.

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🔢 2. Example – Salary Range

SELECT MIN(salary) AS lowest_salary,
       MAX(salary) AS highest_salary
FROM employees;

✅ Shows the salary boundaries in the employees table.

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📅 3. MIN and MAX with Dates

SELECT MIN(hire_date) AS first_hired,
       MAX(hire_date) AS most_recent_hired
FROM employees;

✅ Identifies earliest and latest hiring dates.

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📊 4. Use with GROUP BY

SELECT department,
       MIN(salary) AS min_salary,
       MAX(salary) AS max_salary
FROM employees
GROUP BY department;

✅ Retrieves min and max salary per department.

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🧮 5. Combine with HAVING

SELECT department, MAX(salary) AS top_salary
FROM employees
GROUP BY department
HAVING MAX(salary) > 100000;

✅ Filters groups where top salaries exceed 100,000.

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📉 6. MIN/MAX with Text Columns

SELECT MIN(last_name), MAX(last_name)
FROM employees;

✅ Alphabetically finds the first and last names in the dataset.

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📘 Best Practices

✅ Do This	❌ Avoid This
Alias results for clarity	Leaving raw column names
Pair with GROUP BY for segmentation	Using without context or sorting
Handle NULLs properly (they’re ignored)	Assuming NULL = 0 or ”

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📌 Summary – Recap & Next Steps

The MIN() and MAX() functions are essential for identifying data boundaries, including numeric ranges, date windows, and alphabetical limits.

🔍 Key Takeaways:

• Use MIN() to find the lowest value; MAX() for the highest
• Works with numbers, dates, and strings
• Combine with GROUP BY and HAVING for grouped insights
• Ignores NULLs unless handled using COALESCE()

⚙️ Real-World Relevance:
Used in pricing analytics, trend reports, HR records, audit trails, and data integrity checks.

➡️ Next: Explore COUNT() and conditional aggregation techniques.

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❓ FAQ – SQL MIN and MAX Functions

❓ Do MIN and MAX include NULL values?

✅ No. They ignore NULLs by default.

❓ Can MIN and MAX be used on text columns?

✅ Yes. They return the alphabetically first and last values.

❓ How do I get min/max per category?

✅ Use GROUP BY and select the column you want to group by.

❓ Can I use them in subqueries?

✅ Absolutely. Example:

SELECT name FROM employees
WHERE salary = (SELECT MAX(salary) FROM employees);

❓ Are MIN and MAX efficient?

✅ Yes, especially when used on indexed columns.

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