Menu
What's difference between inner join and outer join (left join,right join), and which has the best performance of them?
Thanks!
895
Different Types of SQL JOINs (INNER) JOIN : Returns records that have matching values in both tables. LEFT (OUTER) JOIN : Returns all records from the left table, and the matched records from the right table. RIGHT (OUTER) JOIN : Returns all records from the right table, and the matched records from the left table.
There are four main types of JOINs in SQL: INNER JOIN, OUTER JOIN, CROSS JOIN, and SELF JOIN.
Basically, we have only three types of joins: Inner join, Outer join, and Cross join. We use any of these three JOINS to join a table to itself.
There are four main types of joins: inner join, full outer join, left outer join and right outer join. The major difference between inner and outer joins is that inner joins result in the intersection of two tables, whereas outer joins result in the union of two tables.
Check this article:
A Visual Explanation of SQL Joins
Inner Join:
Left Outer Join:
Right Outer Join:
150
Performance comparisions between types of joins are irrelevant as they give differnt results sets. Even if an inner join is faster you wouldn't use it if you needed the results of a left join (which includes even the records which don't match the second table in the join).
33
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
