How do you write a SELECT statement in SQL?

Imagine you work for an e-commerce company and are curious about the number of unique products available on your website. You have access to a database with a table named ‘products’ that stores product information. You can use a simple SQL SELECT statement to find out the total number of unique products. 

Here’s an example of a simple query that uses the SELECT clause: 

Let me break down the query to explain how the SELECT clause helped answer the question:

• SELECT: This is the main keyword in the query, which tells the database system that you want to retrieve data.
• product_id, product_name: We want to retrieve these columns from the table. In this case, we are interested in the ‘product_id’ and ‘product_name’ columns. By including these column names after the SELECT keyword, we’re specifying the data we want to see in the output.
• FROM products: This part of the query indicates the source of the data. In this case, we’re specifying that we want to retrieve data from the ‘products’ table.

After executing this query, you’ll get a result set with two columns: ‘product_id’ and ‘product_name,’ containing the respective information for each unique product in the products table. By looking at the total number of rows returned, you can determine the total number of unique products available on your website.