Summarizing Data - MariaDB Crash Course - page 98

▼ Analysis
Here MIN() returns the price of the least expensive item in the products table.
Tip
Using MIN() with Non-Numeric Data As with the MAX() function, MariaDB allows
MIN() to be used to return the lowest value in any columns including textual columns.
When used with textual data, MIN() returns the row that would be first if the data were
sorted by that column.
Note
NULL Values Column rows with NULL values in them are ignored by the MIN()
function.
The SUM() Function
SUM() is used to return the sum (total) of the values in a specific column.
Here is an example to demonstrate this. The orderitems table contains the
actual items in an order, and each item has an associated quantity . The total
number of items ordered (the sum of all the quantity values) can be retrieved
as follows:
▼ Input
SELECT SUM(quantity) AS items_ordered
FROM orderitems
WHERE order_num = 20005;
▼ Output
+---------------+
| items_ordered |
+---------------+
| 19 |
+---------------+
▼ Analysis
The function SUM(quantity) returns the sum of all the item quantities in an
order, and the WHERE clause ensures that just the right order items are included.
SUM() can also be used to total calculated values. In this next example the total
order amount is retrieved by totaling item_price*quantity for each item: