Multi-table join

Multi-table join is a type of database query in which data from two or more related tables in a relational database are combined and joined together. When querying multiple tables, the data must be connected to be retrieved in an organized manner. This type of query can come in many forms, such as an inner join, outer join, or left/right join.

An inner join is a type of join operation that combines two or more tables and is a subset of the Cartesian product. Inner join returns only the result that matches values in both tables.

An outer join is a type of join operation that combines two or more related tables by filtering the rows that do not have a match in both tables. This type of query will return all of the rows from one table and all the rows from the other table that match the criteria from the first.

A left/right join is a type of join operation that combines two related tables from left to right (or right to left). The left/right join will return all the rows from one table and only the matching rows from the other table.

Multi-table joins can be used to join data from two or more different tables into one single result. This type of query is useful when displaying information across multiple tables in an organized manner. While multi-table joins are a powerful feature of relational databases, they can cause a query to take longer to run since more data and resources must be used to process the query.