Microsoft Access Aggregation Query

Microsoft Access databases support multiple aggregation query operations, including the following common aggregation functions: 1. COUNT function: used to calculate the number of records that meet the specified conditions. For example, suppose there is a table called "Orders" that contains fields such as "OrderID", "customerID", "OrderDate", etc. The number of orders can be obtained through the following query: SELECT COUNT(OrderID) AS TotalOrders FROM Orders; 2. SUM function: used to calculate the sum of the specified fields. For example, if there is a table called "Orders" that contains fields such as "OrderID", "customerID", "OrderDate", "TotalAmount", etc., the total order amount can be obtained through the following query: SELECT SUM(TotalAmount) AS TotalSales FROM Orders; 3. AVG function: used to calculate the average value of a specified field. For example, if there is a table called "Products" that contains fields such as "ProductID", "ProductName", "Price", etc., the average value of product prices can be obtained through the following query: SELECT AVG(Price) AS AveragePrice FROM Products; 4. MIN function: used to find the minimum value of the specified field. For example, if there is a table called "Customers" that contains fields such as "Customer ID", "Customer Name", "City", etc., the minimum alphabetical order of city names can be found through the following query: SELECT MIN(City) AS SmallestCity FROM Customers; 5. MAX function: used to find the maximum value of the specified field. For example, suppose there is a table called "Products" that contains fields such as "ProductID", "ProductName", "Price", "Stock", etc. The highest priced product can be found through the following query: SELECT MAX(Price) AS HighestPrice, ProductName FROM Products; 6. GROUP BY clause: used to group the results and calculate the aggregate values for each group. For example, if there is a table called "Orders" that contains fields such as "OrderID", "customerID", "OrderDate", "TotalAmount", etc., the following query can be used to group by customer and calculate the total number of orders and total consumption amount for each customer: SELECT CustomerID, COUNT(OrderID) AS TotalOrders, SUM(TotalAmount) AS TotalSales FROM Orders GROUP BY CustomerID; It is worth noting that the above aggregate queries require the use of aggregate functions in the SELECT statement and, if necessary, grouping operations in conjunction with the GROUP BY clause. The detailed description of the table structure and sample data does not affect the usage of aggregation queries, so only aggregation queries are explained here.