The role of in in mysql

The IN operator in MySQL is used to check whether the value of a column is in a specified list of values, allowing you to easily find records containing a specific value. The syntax is: SELECT column_name FROM table_name WHERE column_name IN (value1, value2, ..., valueN). When using the IN operator, MySQL checks the column values ​​one by one to see if they match any value in the list, and if so, the record is included in the result set.

The role of IN in MySQL

The IN operator is used in MySQL to check whether the value of a column is in in a list of specified values. The IN operator is useful when you need to find records that contain multiple specific values.

Syntax

<code class="sql">SELECT column_name
FROM table_name
WHERE column_name IN (value1, value2, ..., valueN);</code>

Where:

• column_name is the name of the column you want to check.
• value1, value2, ..., valueN is the specific list of values ​​you are looking for.

Usage

When you use the IN operator to query, MySQL checks column values ​​one by one to see if they match any value in the list. If the column value matches any value in the list, the record will be included in the result set.

Example

Suppose you have a table named students which contains student_id, name and age columns. If you want to find students who are 20, 21, or 22 years old, you can use the following query:

<code class="sql">SELECT name
FROM students
WHERE age IN (20, 21, 22);</code>

This query will return the names of all students who are 20, 21, or 22 years old.

Notes

• The IN operator can be used with string, numeric, and date values.
• You can specify any number of value lists.
• The IN operator is similar to the NOT IN operator, which finds records that do not contain any of the values ​​in the list.

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