LESSON 6 Flashcards
Joins allow the retrieval of related data spread across multiple tables in a relational database
Combine Data from Multiple Tables
Joins enable complex queries that
consolidate information for reporting and analytics
Support Advanced Data Analysis
Joins leverage primary and foreign key relationships to link rows in one table to corresponding rows in another.
Establish Relationships Between
Tables
By retrieving only, the required data from multiple tables, JOIN operations reduce redundancy and improve query performance.
Optimize Query Efficiency
Different types of JOINs (INNER, LEFT, RIGHT, FULL OUTER, CROSS) provide flexibility in fetching data depending on the analysis needs
Allow Versatile Data Retrieval
Different types of JOINs
INNER, LEFT, RIGHT, FULL OUTER, CROSS
By linking related tables, JOINs help maintain normalized database structures without duplicating data.
Enhance Data Integrity
JOINs mimic real-world connections between entities, making it easier to model and query practical relationships.
Facilitate Real-World Scenarios
is used to combine rows from two or more tables, based on a related column between them.
JOIN clause
Returns records that have matching values in both tables
INNER JOIN
Returns all records from the left table, and the matched records from the right table
LEFT JOIN:
Returns all records from the right table, and the matched records from the left table
RIGHT JOIN
Returns all records from both tables
CROSS JOIN
return rows when there is at least one match in both tables
Inner Join
does not require each record in the two joined tables to have a matching record
Outer Join
