How does the MIN function work in SQL?

The MIN function in SQL returns the smallest value of the selected column.

The MIN function is an aggregate function that allows you to find the minimum value in a particular column or expression. It is often used in conjunction with the GROUP BY clause to find the minimum value for each group of values. The syntax for the MIN function is straightforward: you simply write "MIN" followed by the column or expression you want to find the minimum value of, all within parentheses.

For example, if you have a table of products with a 'price' column and you want to find the cheapest product, you would use the following SQL statement: "SELECT MIN(price) FROM products;". This would return the lowest price found in the 'price' column.

If you want to find the minimum value for each group of values, you can use the GROUP BY clause. For instance, if you have a table of products with 'category' and 'price' columns and you want to find the cheapest product in each category, you would use the following SQL statement: "SELECT category, MIN(price) FROM products GROUP BY category;". This would return the lowest price for each distinct category in the 'category' column.

It's important to note that the MIN function ignores NULL values. So, if the column or expression you're finding the minimum value of contains NULL values, they will not be considered in the calculation.

The MIN function can be used with numeric, date, and character-based columns, but its behaviour will differ slightly depending on the data type. For numeric and date columns, it will find the smallest numerical or earliest date value respectively. For character-based columns, it will return the value that would come first in alphabetical order.

In summary, the MIN function in SQL is a useful tool for finding the smallest value in a column or expression, and can be used in conjunction with the GROUP BY clause to find the minimum value for each group of values.