Left Join
It is also known as Left Outer Join, returns a table containing all the rows of the left data frame. if there are non-matching rows of the left table then the unmatched data in the right table is replaced by NaN.
Execute a SQL statement:
SELECT table1.col1, table2.col2…
FROM table1
LEFT JOIN table2
ON table1.common_field = table2.common_field;
Code:
Python3
import psycopg2conn = psycopg2.connect( database="EMPLOYEE_DATABASE", user='postgres', password='pass', host='127.0.0.1', port='5432')conn.autocommit = Truecursor = conn.cursor()sql = '''SELECT * from employee left JOIN dept\ON employee.deptno =dept.deptno '''cursor.execute(sql)results = cursor.fetchall()for i in results: print(i)conn.commit()conn.close() |
Output:
Python PostgreSQL – Join
In this article, we are going to see join methods in PostgreSQL using pyscopg2 in Python. Let’s see the type of joins supported in PostgreSQL.