Sql Full Join

SQL full join

Created By: chatGPT

FULL JOIN in SQL, also known as FULL OUTER JOIN, is used to combine records from two tables, returning all records when there is a match in either left or right table records. If there are no matches, the result is filled with NULLs on the side that does not have a match. This is particularly useful when you want to retrieve the full data set from both tables, regardless of whether there is a corresponding row in the other table.

SELECT 
    a.*, 
    b.* 
FROM 
    TableA a 
FULL JOIN 
    TableB b 
ON 
    a.common_column = b.common_column;

In this example, TableA and TableB are joined based on the column common_column. The resulting dataset will include:

All rows from TableA regardless of whether there is a match in TableB.
All rows from TableB even if there is no corresponding row in TableA.

SELECT 
    a.id, 
    a.name, 
    b.age, 
    b.city 
FROM 
    Employees a 
FULL JOIN 
    EmployeesDetails b 
ON 
    a.id = b.employee_id;

Let’s say you have Employees and EmployeesDetails tables. If some employees do not have details and some details do not correspond to any employee, using a full join will help you to view all employees and all the details available along with corresponding values.

SELECT 
    e.name, 
    d.job_title 
FROM 
    Employees e 
FULL JOIN 
    JobDetails d 
ON 
    e.id = d.employee_id;