Between SQL: глубокий взгляд

SQL (Structured Query Language)

SQL (Structured Query Language) is a specialized programming language used for managing and manipulating data in relational databases. One of the most common questions related to SQL is the "between" operator, which allows selecting values from a database within a specific range.

The "between" operator takes three arguments: the start of the range, the end of the range, and the value to be checked. It returns true if the value is within the specified range, and false otherwise.

Here is an example of using the "between" operator:

SELECT *
FROM employees
WHERE salary BETWEEN 1000 AND 2000;

By executing this query, we will retrieve all employees whose salary is within the specified range. This is an example of a simple usage of the "between" operator.

However, the "between" operator can be applied not only to numbers but also to strings and dates. Here are examples of using the "between" operator for different data types:

1. For string values:

SELECT *
FROM products
WHERE category BETWEEN 'A' AND 'B';

2. For dates:

SELECT *
FROM orders
WHERE order_date BETWEEN '2021-01-01' AND '2021-12-31';

In this example, we are selecting all orders made within the year 2021.

It is worth noting that the "between" operator includes the values specified at the start and end of the range. If you need to exclude one or both of the endpoint values, you can use the ">" (greater than), "<" (less than), ">=" (greater than or equal to), or "<=" (less than or equal to) operators.

For example, to select all employees whose salary is within the range from 1000 (inclusive) to 2000 (exclusive), you can write the following query:

SELECT *
FROM employees
WHERE salary >= 1000 AND salary < 2000;

In this case, employees with a salary equal to 2000 are not included in the result set.

In conclusion, the "between" operator is a powerful tool in SQL that allows for easy selection of values from a database within a specified range. It can also be applied to various data types, including numbers, strings, and dates.