Difference between inner join and left join in SQL
In SQL, both INNER JOIN and LEFT JOIN are used to combine rows from two or more tables based on a related column between them.The difference between inner join and left join in SQL is:
INNER JOIN :
When you use an INNER JOIN, it finds records in both tables that match the join condition you give it.
Rows from the tables that don’t meet the join condition are left out of the set of results.
The result set only has rows where the values in the given column(s) are the same in both tables.
In the above example the rows having department_id values in both the employees and departments tables will be included in the result.
LEFT JOIN (or LEFT OUTER JOIN):
As the name implies, a LEFT JOIN obtains both the left table (the one mentioned before the LEFT JOIN) and the right table that matches the join criteria.
Columns from the correct table will return NULL if there is no matching record.
All rows from the left table are included in the final set, regardless of whether or not they have a corresponding entry in the right table.
In the above instance, the result will include all customers, and if a customer has placed an order, that order’s specifics will also be displayed. Columns in the orders table will be empty if the corresponding customer has not yet placed any orders.
Overall, INNER JOIN only gives back the rows that match, while LEFT JOIN gives back all the rows from the left table plus the matched rows from the right table, leaving empty rows in the right table for rows that don’t match. we hope that the above article helps our readers to be clear about the Difference between inner join and left join in SQL.You can also view other related articles What is Database and Characteristics of data in Database?