Understanding Division Operator in MariaDB SQL Statements

Functionality

• Can be used within various SQL statements like SELECT, UPDATE, and DELETE along with clauses like WHERE and ORDER BY.
• Performs mathematical division, dividing the value on the left by the value on the right.

Result

• Dividing by zero will result in NULL.
• By default, the result will include up to four decimal places. This is controlled by the server variable div_precision_increment, which can be adjusted from 0 to 30 decimal places.

Here are some things to keep in mind

• For non-integer operands (numbers with decimals) exceeding the BIGINT range, DIV might produce incorrect results.
• MariaDB also offers the DIV operator, which performs integer division. This is similar to the FLOOR() function but works safely with even larger integer values (BIGINT).

Example

SELECT product_price / quantity_sold AS unit_price
FROM sales_data;

In this example, the SELECT statement calculates the unit price by dividing product_price by quantity_sold. The result (unit_price) will have the price per unit of the product, potentially with up to four decimal places.

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Calculating Average

SELECT AVG(price) AS average_price
FROM products;

This code calculates the average price of all products in the products table. The AVG function takes the average of all price values and the division (/) implicitly happens within the function.

Finding Discounts

SELECT product_name, price * (1 - discount / 100) AS discounted_price
FROM products;

This code calculates the discounted price for each product. It multiplies the original price by (1 minus the discount divided by 100). This effectively calculates a percentage discount.

Checking Inventory Ratios

SELECT product_name, stock / reorder_level AS stock_ratio
FROM inventory;

This code calculates the stock ratio for each product in the inventory table. It divides the current stock level by the reorder_level. This helps identify products nearing their reorder point.

Using DIV for Integer Division

SELECT total_points DIV games_played AS points_per_game
FROM player_stats;

This code uses the DIV operator to calculate the average points per game for each player in the player_stats table. Since DIV performs integer division, it truncates any decimals and provides the whole number of points per game.

Combining Division with Other Operators

SELECT customer_id, (order_total - discount) / shipping_cost AS cost_per_unit_shipped
FROM orders;

This code showcases combining division with other operators. It calculates the cost per unit shipped for each order. It subtracts the discount from the order_total and then divides by the shipping_cost.

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Using Functions

• POWER(x, -1)
  This function raises the first operand (x) to the power of -1. It's mathematically equivalent to division, but can be less intuitive.

SELECT product_price * POWER(quantity_sold, -1) AS unit_price
FROM sales_data;

CASE Statement with WHEN clause

This approach is useful for handling specific division scenarios, especially when dealing with potential division by zero.

SELECT product_name,
  CASE WHEN quantity_sold = 0 THEN 0  -- Handle division by zero
       ELSE product_price / quantity_sold AS unit_price
  END
FROM sales_data;

COALESCE Function (for handling division by zero)

This function allows you to specify a default value if the division results in NULL (division by zero).

SELECT product_name,
  COALESCE(product_price / quantity_sold, 0) AS unit_price
FROM sales_data;

• Using POWER(x, -1) is generally less common and might be less readable compared to the division operator.
• If you need to handle potential division by zero or implement specific logic based on the result, consider using the CASE statement or COALESCE function.
• For simple division, the division operator (/) remains the most efficient and readable option.