What is the Difference Between Inner Join and Natural Join?

The main difference between an inner join and a natural join in SQL lies in the join condition:

• Inner Join: This join operation combines two tables based on a specific join condition, formed by matching column values of the two tables according to the join-predicate. Inner joins can use any comparison operator, such as =, <=, >=, <, >, or <>.
• Natural Join: This join operation merges two tables based on matching column names and data types. Natural joins do not require an explicit join condition, as they combine tables when they share a column name.

In summary, inner joins require a specific join condition, whereas natural joins combine tables based on matching column names and data types without the need for an explicit join condition. Some other differences between inner and natural joins include:

• The final table resulting from a natural join will contain all the attributes of both the tables without duplicating any columns. In contrast, the final table resulting from an inner join will contain all the attributes of both the tables, including duplicate columns.
• SQL Server Management Studio supports inner joins but does not support natural joins.
• Natural joins can also be outer joins (left, right, or full), while inner joins can only be inner joins.

Comparative Table: Inner Join vs Natural Join

The main differences between an inner join and a natural join are as follows:

Here's an example of each type of join:

• Inner Join: SELECT * FROM table1 INNER JOIN table2 ON table1.column_name = table2.column_name;
• Natural Join: SELECT * FROM table1 NATURAL JOIN table2;

Both inner and natural joins combine rows from two tables based on a common column. However, a natural join simplifies the syntax by automatically joining tables with matching column names and data types, while an inner join requires an explicit join condition.