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📚 LEFT JOIN

The LEFT JOIN is used in SQL to combine rows from two tables.
It returns all records from the left table and the matching records from the right table.
If there is no match, the result is NULL on the right side.

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🛠️ Basic Syntax

SELECT columns
FROM table1
LEFT JOIN table2
ON table1.column_name = table2.column_name;

• LEFT JOIN keeps all records from the left table.
• If no matching record exists in the right table, NULL values are returned for the right table’s columns.

Example

SELECT employees.first_name, departments.department_name
FROM employees
LEFT JOIN departments
ON employees.department_id = departments.department_id;

• This query returns all employees and their department names.
• If an employee does not belong to any department, the department name will be NULL.

Key Points

• LEFT JOIN is also known as LEFT OUTER JOIN.
• All records from the left table appear in the result set.
• Only matching records from the right table are included.
• Useful for identifying unmatched or orphan records.

Additional Example

SELECT customers.customer_name, orders.order_id
FROM customers
LEFT JOIN orders
ON customers.customer_id = orders.customer_id;

• This query lists all customers and their corresponding order IDs, even if they haven't placed any orders.

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🎥 Video Notes

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📝 Problem Description

Describe the problem, challenge, or topic discussed in a video related to SELECT FROM.
What concept was explained or what exercise was solved?

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DataBase Given

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💻 My SQL Code

-- Write your SQL code attempt or solution related to SQL COMMAND
SQL COMMAND

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🧠 Solution Code / Explanation

SQL COMMAND

Explanation - Explain what you learned, any key takeaways, or how you solved the problem related to COMMAND._

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