VelocityDB aggregation query

VelocityDB is a high-performance object-oriented embedded database. It supports various types of queries, including aggregated queries. The following are some common aggregation queries supported by VelocityDB and provided examples: 1. Count: Used to calculate the number of records for a given condition. Example: Counting the number of users with male gender in the user table. Table structure: User (name, gender) Sample data: Jack (male), Emily (female), Alex (male), Olivia (female) Query: SELECT COUNT (*) From User WHERE Gender='Male' 2. Sum: Used to calculate the sum of values for a column under given conditions. Example: Calculate the total sales revenue of all products in the order table. Table structure: Order (order number, product name, sales amount) Sample data: 1, A, 100; 2, B, 200; 3, C, 150 Query: SELECT SUM (Sales) From Order 3. Averaging (avg): Used to calculate the average value of a column's values under given conditions. Example: Calculate the average price of all products in the product table. Table structure: Product (product name, price) Sample data: A, 100; B. 200; C. 150 Query: SELECT AVG (Price) From Product 4. Max and Min: Used to find the maximum and minimum values of a column under given conditions. Example: Find the maximum and minimum height values in the student table. Table structure: Student (name, height) Sample data: Jack, 180; Emily, 170; Alex, 185; Olivia, 165 Query: SELECT MAX (height), MIN (height) from Student 5. Group by: Used to group records based on given conditions and perform aggregation calculations on each group. Example: Counting the quantity of each type of product in the product table. Table structure: Product (product name, type) Sample data: A, type 1; B. Type 2; C. Type 1; D. Type 2 Query: SELECT type, COUNT (*) From Product GROUP BY type 6. Order by: Used to sort records according to given conditions. Example: Sort the order table in descending order based on sales revenue. Table structure: Order (order number, product name, sales amount) Sample data: 1, A, 100; 2, B, 200; 3, C, 150 Query: SELECT * From Order Order BY Sales DESC These are some examples of aggregated queries supported by VelocityDB. By using these query statements, data can be easily counted and analyzed to meet business needs. The actual query syntax and table structure may vary depending on the application and specific requirements.