Usage of wherein in sql

WHERE IN in SQL is used to check whether a column contains a specific set of values. Syntax: SELECT column_name FROM table_name WHERE column_name IN (value1, value2, ..., valueN);. It checks if each value in the column matches any value in the given list of values ​​and returns the row if it matches, otherwise ignores the row.

Usage of WHERE IN in SQL

The WHERE IN operator is used to check whether a column contains a specific set of value. It uses the following syntax:

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

How it works

The WHERE IN operator checks whether each value in a column matches any value in the given list of values. If there is a match, the corresponding row is returned; if there is no match, the row is ignored.

Example

Suppose we have a table called "users" with the following columns:

• id
• name
• email

To find the email address of a user named "John" or "Mary", you can use the following query:

<code>SELECT email
FROM users
WHERE name IN ('John', 'Mary');</code>

This will return rows with the name "John" or "Mary" as follows:

<code>email
-----------------
john@example.com
mary@example.com</code>

Note:

• Lists of values ​​can use single quotes (' ) or enclosed in double quotes (").
• The IN operator can also be used with subqueries.
• The WHERE IN operator may be less efficient for large lists of values. Consider using JOIN or EXISTS operator as an alternative.

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