WeiDa can retrieve data from multiple data tables in a data source through SQL queries. For example, assume there are two data tables: "Orders" and "Customers". The "Orders" table contains order information such as order ID, customer ID, and order amount, while the "Customers" table contains customer information such as customer ID and customer name.
To calculate the total order amount of each customer, a SQL query can be used to join these two tables based on the customer ID field and perform aggregation calculations. The following is a simple example of an SQL statement:
SELECT c.customer_name, SUM(o.order_amount) AS total_amount
FROM Customers c
JOIN Orders o ON c.customer_id = o.customer_id
GROUP BY c.customer_name;
This query joins the "Customers" and "Orders" tables through the "customer_id" field, and then groups the results by customer name and calculates the total order amount for each customer.
After obtaining the calculation result, WeiDa can display it on the page. Usually, a front-end development framework is used to render the data on the web page. For example, use JavaScript and a front-end framework like Vue.js. First, send an asynchronous request to the server through an API to obtain the calculation result data. Then, update the data in the Vue.js component, and use the template syntax of Vue.js to dynamically display the data on the HTML page.
In a cloud computing environment, if you need to store and manage large amounts of data, Tencent Cloud's Cloud Block Storage (CBS) can provide stable and reliable block storage services to store data sources. Tencent Cloud's Cloud Database MySQL can be used to store and manage structured data such as the above-mentioned "Customers" and "Orders" tables, providing efficient data query and processing capabilities.