EXtremeDB aggregation query

EXtremeDB is a In-memory database management system that supports various aggregate queries. It provides a set of aggregation functions, such as SUM, COUNT, AVG, MIN, and MAX, that can be used in queries to perform aggregation operations. Here are some common aggregation queries and examples: 1. Sum (SUM): Suppose there is a table called "Orders" that contains columns such as order ID, customer ID, and total order amount. To calculate the total order amount for a certain customer, the following query can be used: SELECT SUM(OrderAmount) AS TotalAmount FROM Orders WHERE CustomerID = '123456' This query will return the total amount of all orders for the specified customer. 2. Count: If you want to obtain the order quantity in the order table, you can use the COUNT function. The following is an example query: SELECT COUNT(*) AS TotalOrders FROM Orders This query will return the total number of rows in the order table, which is the order quantity. 3. AVG: Suppose there is a table called "Products" that contains columns such as product ID, product name, and product price. To calculate the average price of all products, you can use the following query: SELECT AVG(Price) AS AveragePrice FROM Products This query will return the average price of all products. 4. Min and Max values: If you want to obtain the cheapest and most expensive product prices in the product list, you can use the MIN and MAX functions. The following is an example query: SELECT MIN(Price) AS MinPrice, MAX(Price) AS MaxPrice FROM Products This query will return the lowest and highest product prices in the product table. It should be noted that the above example assumes that the table structure has been defined and includes sample data. The specific table structure and sample data can be defined according to actual needs.