#INNER JOIN EXAMPLE POSTGRESQL HOW TO#

The department_id column in the employees table is the foreign key column that links the employees to the departments table. The relationship between the departments and employees is one-to-many. We will use the employees and departments tables from the sample database to demonstrate how the INNER JOIN clause works.Įach employee belongs to one and only one department while each department can have more than one employee. 1) Using SQL INNER JOIN to join two tables example

Let’s take some practical examples of using the INNER JOIN clause. INNER JOIN C ON C.n = A.n Code language: SQL (Structured Query Language) ( sql ) SQL INNER JOIN examples

#INNER JOIN EXAMPLE POSTGRESQL HOW TO#

The INNER JOIN clause can join three or more tables as long as they have relationships, typically foreign key relationships.įor example, the following statement illustrates how to join 3 tables: A, B, and C: SELECT This condition is called join condition i.e., B.n = A.n

The condition to match between table A and table B is specified after the ON keyword. The INNER JOIN clause appears after the FROM clause. INNER JOIN B ON b = a Code language: SQL (Structured Query Language) ( sql ) The following statement illustrates the inner join clause: SELECT a Suppose the columns in the A and B tables are a and b. If a row is matched, it is included in the final result set. For each row in table A, the inner join clause finds the matching rows in table B.

Inner join example postgresql