SQL COUNT / SUM / AVG / MIN / MAX

Article Summary

Aggregate functions perform calculations on multiple rows and return a single value β€” ideal for reports, summaries, and analysis. πŸ”Ή Syntax & Examples πŸ”Ή With GROUP BY 🧠 Quick Recap Function Description COUNT Count rows (or non-null values) SUM Total of values AVG Average value MIN Smallest value MAX Largest value βœ… Use these to […]

Aggregate functions perform calculations on multiple rows and return a single value β€” ideal for reports, summaries, and analysis.

πŸ”Ή Syntax & Examples

-- βœ… COUNT: Total number of rows (non-null values in a column)
SELECT COUNT(*) FROM employees;
SELECT COUNT(salary) FROM employees WHERE department = 'IT';

-- βœ… SUM: Total of a numeric column
SELECT SUM(salary) FROM employees WHERE department = 'HR';

-- βœ… AVG: Average of a numeric column
SELECT AVG(salary) FROM employees;

-- βœ… MIN / MAX: Lowest / Highest value
SELECT MIN(salary) FROM employees;
SELECT MAX(salary) FROM employees;

πŸ”Ή With GROUP BY

-- Average salary per department
SELECT department, AVG(salary)
FROM employees
GROUP BY department;

-- Count of employees in each department
SELECT department, COUNT(*)
FROM employees
GROUP BY department;

🧠 Quick Recap

FunctionDescription
COUNTCount rows (or non-null values)
SUMTotal of values
AVGAverage value
MINSmallest value
MAXLargest value

βœ… Use these to summarize and analyze your data

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