Difference Between Inner Join and Outer Join in SQL
In this post, we will understand the difference between inner join and outer join in SQL.
Inner Join
The clause used is ‘INNER JOIN’ and ‘JOIN’.
It returns the combined tuple of two or more tables.
When no attributes are common, the result is empty.
If the number of tuples is more, then ‘INNER JOIN’ works quickly in comparison to ‘OUTER
JOIN’.
It is used when detailed information about a specific attribute is required.
The ‘JOIN’ and ‘INNER JOIN’ work in the same manner.
Syntax
SELECT *
FROM table_1 INNER JOIN / JOIN table_2
ON table_1.column_name = table_2.column_name;
Outer Join
It returns the combined tuple of a specified table.
It is returned even when the ‘JOIN’ condition fails.
The clauses LEFT OUTER JOIN, RIGHT OUTER JOIN, FULL OUTER JOIN can be used.
It doesn’t depend on the common attributes.
If the attribute is blank, NULL is placed instead of the blank.
The ‘OUTER JOIN’ is slow in comparison to ‘INNER JOIN’.
It is used when complete information is required.
FULL OUTER JOIN and FULL JOIN clauses work in the same manner.
Syntax
SELECT *
FROM table_1 LEFT OUTER JOIN / RIGHT OUTER JOIN /
FULL OUTER JOIN / FULL JOIN table_2 ON
Table_1.column_name = table_2.column_name;
Published on 15-Apr-2021 11:14:19
