Beginner

651. EQUI JOIN

Understand the traditional equality-based JOIN pattern.

📘 Lesson 651 of 728 ⏱ 13 min 🎯 Intermediate

An EQUI JOIN matches rows from two tables when the specified columns have equal values.

Most relational JOINs use equality between primary and foreign keys.

Match employees with their departments using DepartmentID.

SQL 
SELECT
    e.EmployeeName,
    d.DepartmentName
FROM Employees e
INNER JOIN Departments d
    ON e.DepartmentID = d.DepartmentID;

Used in almost every relational reporting and transactional application.

  • Uses the equality operator =.
  • Usually matches related key columns.
  • INNER JOIN is commonly used for EQUI JOIN logic.
  • Can be combined with other conditions.
  • It is the most common JOIN pattern.
What is an EQUI JOIN?

An EQUI JOIN matches rows using an equality condition between columns.

Where are EQUI JOINs commonly used?

They are commonly used to connect primary keys with foreign keys.

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