What does or mean in mysql

In MySQL, the OR operator (||) connects multiple conditions and returns true as long as one of the conditions is true. It is used to find data that meets multiple criteria, combine subquery results, and create complex search criteria.

The meaning of OR operator in MySQL

In MySQL, the OR operator (||) is used Concatenates two or more conditions and returns true if any one of the conditions is true. It is a logical operator that can be used to create more complex and flexible queries.

Syntax

<code>条件1 || 条件2 || ...</code>

Where Condition 1, Condition 2, etc. are Boolean expressions or subqueries.

Usage

The OR operator can be used in the following situations:

• Find data that meets multiple conditions: For example, find orders with sales of more than $100 or where the customer name contains "John".
• Combining the results of multiple subqueries: For example, find records that match data in table A or match data in table B.
• Create complex search criteria: For example, find data that meets specific criteria or belongs to a specific group.

Example

<code>SELECT * FROM users WHERE username = 'john' OR email = 'john@example.com';</code>

This query will return all users with the username "john" or the email address "john@example.com".

<code>SELECT * FROM products WHERE price > 100 OR category = 'electronics';</code>

This query will return all products that cost more than $100 or are in the "electronics" category.

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