Usage of in in sql

The IN operator in SQL checks whether a value is contained in a given list of values: Syntax: column_name IN (value1, value2, ..., valueN) When the value in column_name matches any value in the list Returns true when matching, otherwise returns false Advantage: More efficient than other equality operators when checking multiple values

IN usage in SQL

IN is an operator in SQL used to check whether a value exists in a given list. The syntax is as follows:

<code>column_name IN (value1, value2, ..., valueN)</code>

Where:

• column_name is the column in which the value to be checked is located.
• value1, value2, ..., valueN is the list of values ​​to check.

The IN operator returns true when the value in column_name matches any value in the list; otherwise it returns false.

Usage examples

The following are some usage examples of the IN operator:

-- 检查员工表中 id 为 1 的员工的姓名
SELECT name FROM employees WHERE id IN (1);

-- 检查产品表中价格在 100 到 200 美元之间的产品的名称
SELECT name FROM products WHERE price IN (100, 200);

-- 检查订单表中包含特定客户 ID 的订单号
SELECT order_id FROM orders WHERE customer_id IN (123, 456);

Notes

• The IN operator can check multiple values.
• The value in the IN operator can be a constant, a field, or the result of a subquery.
• The IN operator is generally more efficient than other operators that check for value equality, such as = or <>.
• The IN operator does not sort the values ​​in the list.
• If the list contains null values, the IN operator will return null.

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