Difference between Natural join and Inner Join in SQL

The join operation merges the two tables based on the same attribute name and their datatypes are known as Natural join Unlike INNER JOIN, which requires you to specify the columns and conditions for the join explicitly. In this article, we will also see the differences between them. Let’s start with Natural Join.

Example:

If you have two tables “Student” and “Student_Marks” and you want to retrieve a record of students who have got marks then we use INNER JOIN using a shared column like ”ROLL_No”.

NATURAL JOIN

Natural Join in SQL joins two tables based on the same attribute name and datatypes. The resulting table will contain all the attributes of both tables but keep only one copy of each common column.

Syntax 

SELECT * 
FROM table1 NATURAL JOIN table2; 

Example
Consider the two tables given below the first one is the Student Table and the Second is the Student_Marks with the help of these two tables we are doing INNER and NATURAL JOINS operations on the table.

Creating Student Table Query

CREATE TABLE Student(
  Roll_No INT PRIMARY KEY,
  Name VARCHAR(50));
--Insert the value in the Student table
  INSERT INTO Student VALUES
  (1,'Mohit'),
  (2,'Aman'),
  (3,'Sachin'),
  (4,'Manish');

Output

Student Table

Query for Marks Table

CREATE TABLE Student_Marks(
  Roll_No INT PRIMARY KEY,
  Marks INT);
  INSERT INTO Student_marks VALUES
  (2,82),
  (3,96),
  (4,39),
  (5,98);

Output

Student_Marks Table

Example:

Query

SELECT * 
FROM Student NATURAL JOIN Student_Marks;

Output

Table 1

INNER JOIN

Inner Join joins two table on the basis of the column which is explicitly specified in the ON clause. The resulting table will contain all the attributes from both the tables including common column also. 

Syntax

SELECT * 
FROM table1 INNER JOIN table2 ON table1.Column_Name = table2.Column_Name; 

Query

Consider the above two tables and the query is given below:

SELECT * 
FROM Student S INNER JOIN Student_Marks M ON S.Roll_No = M.Roll_No; 

Output

Table 2

Natural JOIN vs INNER JOIN in SQL

NATURAL JOIN	INNER JOIN
Natural Join joins two tables based on same attribute name and datatypes.	Inner Join joins two table on the basis of the column which is explicitly specified in the ON clause.
In Natural Join, The resulting table will contain all the attributes of both the tables but keep only one copy of each common column	In Inner Join, The resulting table will contain all the attribute of both the tables including duplicate columns also
In Natural Join, If there is no condition specifies then it returns the rows based on the common column	In Inner Join, only those records will return which exists in both the tables
Syntax-  SELECT *  FROM table1 NATURAL JOIN table2;	Syntax- SELECT *  FROM table1 INNER JOIN table2 ON table1.Column_Name= table2.Column_Name;

The Natural Joins are not supported in the SQL Server Management Studio also known as Microsoft SQL Server.

Conclusion

In this post, we have mostly discussed the NATURAL JOIN and INNER JOIN as well as their distinctions. In the structured query language, both types of joins—whether they be Natural joins or Inner joins—play a significant role. An explicit join condition is not necessary for a natural join. The primary distinction is that whereas natural joins combine tables when they share a column name, inner joins combine tables that are expressly defined in the ON clause.