Join Three or More Tables in SQL

To join three or more tables, simply repeat the JOIN clause repeatedly. See the syntax below, where INNER JOIN clause is used to join three tables. Any other JOIN type can be used in the same way. Similarly, it can be used to join any number of tables.

Syntax

The syntax for joining three tables using INNER JOIN keyword is given below:

SELECT table1.column1, table1.column2, ... 
  table2.column1, table2.column2, ...
  table3.column1, table3.column2, ...
FROM table1 INNER JOIN table2
  ON table1.matching_column = table2.matching_column
INNER JOIN table3
  ON table1.matching_column = table3.matching_column;

Example:

Consider a database containing tables called Employee, Bonus_Paid and Contact_Info with the following records:

Table 1: Employee table

Table 2: Bonus_Paid table

Table 3: Contact_Info table

• To fetch a record containing EmpID, Name, Bonus and Address from these tables, the following SQL query can be used:

  SELECT Employee.EmpID, Employee.Name, 
    Bonus_Paid.Bonus, Contact_Info.Address
  FROM Employee INNER JOIN Bonus_Paid
    ON Employee.EmpID = Bonus_Paid.EmpID
  INNER JOIN Contact_Info
    ON Employee.EmpID = Contact_Info.EmpID;
  

  
  

  This will produce the result as shown below:

  EmpID	Name	Bonus	Address
  2	Marry	400	Brooklyn, New York, USA
  3	Jo	450	Grenelle, Paris, France
  4	Kim	550	Geuzenveld, Amsterdam, Netherlands
  6	Huang	600	Yizhuangzhen, Beijing, China

• To fetch the above record but with a condition like Bonus should be greater than equal to 500, the following SQL query can be used:

  SELECT Employee.EmpID, Employee.Name, 
    Bonus_Paid.Bonus, Contact_Info.Gender, 
    Contact_Info.Address
  FROM Employee INNER JOIN Bonus_Paid
    ON Employee.EmpID = Bonus_Paid.EmpID
  INNER JOIN Contact_Info
    ON Employee.EmpID = Contact_Info.EmpID
  WHERE Bonus_Paid.Bonus >= 500;
  

  
  

  This result of the following code will be:

  EmpID	Name	Bonus	Address
  4	Kim	550	Geuzenveld, Amsterdam, Netherlands
  6	Huang	600	Yizhuangzhen, Beijing, China