Description: A range query is an operation in databases that allows retrieving a set of data that falls within a specific interval. This type of query is fundamental for data manipulation and analysis, as it enables users to filter information efficiently. Typically, it is used in conjunction with clauses like ‘WHERE’ in SQL, where the lower and upper limits of the desired range are specified. Range queries are particularly useful in situations where numerical data, dates, or any other type of information that can be ordered needs to be analyzed. For example, they can be used to obtain all sales made between two specific dates or to list all products whose price falls within a certain range. The ability to perform range queries not only enhances the efficiency of data retrieval but also allows analysts and developers to make informed decisions based on relevant and specific datasets.
History: Range queries have existed since the inception of relational databases in the 1970s when the relational model was introduced by Edgar F. Codd. As databases evolved, so did the querying capabilities, allowing users to perform more complex and specific searches. With the development of SQL (Structured Query Language) in the 1980s, range queries were standardized and became an integral part of database interaction, facilitating data retrieval within defined intervals.
Uses: Range queries are used in a variety of applications across different fields, from database management systems to data analytics. They are essential in e-commerce for filtering products by price, in inventory management systems for tracking items within a date range, and in statistical analysis for extracting relevant data from large datasets. They are also common in financial analysis applications, where evaluating asset performance over a specific period is required.
Examples: A practical example of a range query would be an SQL statement that retrieves all sales orders made between January 1, 2023, and December 31, 2023: ‘SELECT * FROM sales WHERE sale_date BETWEEN ‘2023-01-01’ AND ‘2023-12-31′;’. Another example could be retrieving all employees whose salary is between 30000 and 50000: ‘SELECT * FROM employees WHERE salary BETWEEN 30000 AND 50000;’.
