A subquery, also known as an inner query or nested query, is a query nested within another SQL query. Subqueries are often used to retrieve data that will be used in the main query to further filter, ...

-- 2. Get data from the sales table, product name, and category in the result set. (select Customer_Name from customer where Customer_ID = sales.Customer_ID) AS Customer_Name, (select Age from ...

operand is one of the following: constant is a number or a quoted character string (or other special notation) that indicates a fixed value. Constants are also called literals. Constants are described ...