SQL OR Operator

SQL OR Operator

The SQL OR operator is used to combine multiple conditions in a SQL query's WHERE clause. This command is essential for retrieving rows that meet at least one of the specified criteria, allowing for flexible and broad data filtering.

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Syntax

SELECT column1, column2, ...
FROM table_name
WHERE condition1 OR condition2 OR ...;

• SELECT: This is the SQL keyword used to specify the columns to retrieve.
• column1, column2, ...: These specify the names of the columns to retrieve.
• FROM: This is the SQL keyword used to specify the table.
• table_name: This specifies the name of the table from which to retrieve the rows.
• WHERE: This is the SQL keyword used to specify the conditions for filtering the rows.
• condition1, condition2, ...: These specify the conditions that the rows must meet to be retrieved.

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Example

Let's go through a complete example that includes creating a database, creating a table, inserting data into the table, and then using the OR operator to filter specific rows based on multiple conditions.

Step 1: Creating a Database

This step involves creating a new database named example_db.

CREATE DATABASE example_db;

In this example, we create a database named example_db.

Step 2: Creating a Table

In this step, we create a table named employees within the previously created database.

USE example_db;

CREATE TABLE employees (
    id INT AUTO_INCREMENT PRIMARY KEY,
    first_name VARCHAR(50) NOT NULL,
    last_name VARCHAR(50) NOT NULL,
    email VARCHAR(100),
    hire_date DATE
);

Here, we define the employees table with columns for id, first_name, last_name, email, and hire_date. The id column is set as the primary key and will auto-increment.

Step 3: Inserting Data into the Table

This step involves inserting some sample data into the employees table.

INSERT INTO employees (first_name, last_name, email, hire_date) VALUES ('John', 'Doe', 'john.doe@example.com', '2023-01-01');
INSERT INTO employees (first_name, last_name, email, hire_date) VALUES ('Jane', 'Smith', 'jane.smith@example.com', '2023-02-01');
INSERT INTO employees (first_name, last_name, email, hire_date) VALUES ('Alice', 'Johnson', 'alice.johnson@example.com', '2023-03-01');
INSERT INTO employees (first_name, last_name, email, hire_date) VALUES ('Bob', 'Brown', 'bob.brown@example.com', '2023-04-01');

Here, we insert four rows of data into the employees table.

Step 4: Using the OR Operator

This step involves retrieving rows from the employees table where the last_name is 'Doe' or the hire_date is '2023-02-01'.

SELECT * FROM employees
WHERE last_name = 'Doe' OR hire_date = '2023-02-01';

This command will return the rows from the employees table where the last_name is 'Doe' or the hire_date is '2023-02-01'.

You can also use the OR operator with other conditions and comparison operators, such as:

• = (equal to)
• != or <> (not equal to)
• > (greater than)
• < (less than)
• >= (greater than or equal to)
• <= (less than or equal to)
• LIKE (pattern matching)
• IN (matching any value in a list)
• BETWEEN (within a range of values)

For example, to retrieve rows where the last_name is 'Doe' or the email contains 'example.com':

SELECT * FROM employees
WHERE last_name = 'Doe' OR email LIKE '%example.com';

This command will return the rows from the employees table where the last_name is 'Doe' or the email contains 'example.com'.