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📚 JOIN WITH WHERE

Using a JOIN with a WHERE clause in SQL allows you to combine rows from multiple tables and then apply additional filters after the join.
This approach helps narrow down the result set based on specific conditions.

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🛠️ Basic Syntax

SELECT columns
FROM table1
JOIN table2
ON table1.column_name = table2.column_name
WHERE condition;

• JOIN combines rows based on a related column between tables.
• WHERE filters the joined data based on specific criteria.

Example

SELECT employees.first_name, departments.department_name
FROM employees
INNER JOIN departments
ON employees.department_id = departments.department_id
WHERE departments.location = 'New York';

• This query lists employees who work in departments located in New York.

Key Points

• The JOIN happens first, then WHERE filters the combined result.
• Filtering with WHERE is different from filtering by modifying the join itself (like LEFT JOIN ... WHERE table2.column IS NULL).
• Be cautious: a WHERE clause can turn an OUTER JOIN into an INNER JOIN if not written properly.

Additional Example

SELECT customers.customer_name, orders.order_id
FROM customers
LEFT JOIN orders
ON customers.customer_id = orders.customer_id
WHERE orders.order_date >= '2024-01-01';

• This query returns customers and their orders placed on or after January 1, 2024.

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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

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SQL COMMAND

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🧠 Solution Code / Explanation

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