The SELF JOIN is used to join the table to itself, assuming it as two tables.
- Syntax of SELF JOIN –
SELECT A.column_name,B.column_name,... FROM Table A ,Table B WHERE condition ;
Example – Consider the Product table to use Self join.
Demo Table –
Product Table
| Category | Region | City | Country | Customer_ID | Customer_name |
| Office Supplies | Central | Chicago | United States | SM-20950 | Suzanne McNair |
| Technology | East | New York City | United States | AH-10465 | Amy Hunt |
| Office Supplies | East | New York City | United States | AH-10465 | Amy Hunt |
| Office Supplies | East | Dover | United States | EP-13915 | Emily Phan |
| Office Supplies | East | Dover | United States | EP-13915 | Emily Phan |
| Technology | West | Aurora | United States | TP-21565 | Tracy Poddar |
| Office Supplies | West | Aurora | United States | TP-21565 | Tracy Poddar |
| Office Supplies | East | Long Beach | United States | AR-10825 | Anthony Rawles |
| Office Supplies | West | Pasadena | United States | HA-14920 | Helen Andreada |
| Furniture | West | Pasadena | United States | HA-14920 | Helen Andreada |
Now, suppose we want to see those customers that belong to the same cities.
SELECT A.[Customer Name] AS Customer_Name1,B.[Customer Name] AS Customer_name2, A.City
FROM [dbo].[Products] AS A , [dbo].[Products] AS B
WHERE A.[Customer ID] != B.[Customer ID]
AND A.City = B.City ;
This output is the small section of the output by executing the above query –
| Customer_Name1 | Customer_Name2 | City |
| Aaron Bergman | Adam Bellavance | Seattle |
| Aaron Bergman | Adam Hart | Arlington |
| Aaron Bergman | Alan Hwang | Seattle |
| Aaron Bergman | Alejandro Ballentine | Seattle |
| Aaron Bergman | Alejandro Savely | Seattle |
| Aaron Bergman | Amy Cox | Seattle |
| Aaron Bergman | Andrew Gjertsen | Seattle |
| Aaron Bergman | Angele Hood | Seattle |
| Aaron Bergman | Ann Chong | Seattle |
| Aaron Bergman | Ann Steele | Seattle |
Follow us on Twitter, Facebook, Linkedin, and Tableau Public to stay updated with our latest blog and what’s new in Tableau.
If you are looking forward to getting your data pipeline built and setting up the dashboard for business intelligence, book a call now from here.
#analytics #data #business #artificialintelligence #machinelearning #startup #deeplearning #deeplearning #datascience #ai #growth #dataanalytics #india #datascientist #powerbi #dataanalysis #tableau #SQL #businessanalytics #businessanalyst #businessandmanagement #dataanalyst #businessanalysis #analyst #analysis #powerbideveloper #powerbidesktop #letsviz
