In SQL, an outer join is a type of join that returns all rows from one table and the matching rows from another table, even if there are no matching rows in the second table. This can lead to a large number of unnecessary rows being returned, which can slow down your query and make it more difficult to work with the data.There are a few different ways to avoid outer joins. One way is to use an inner join, which only returns rows that have matching values in both tables. Another way is to use a left join or a right join, which returns all rows from one table and the matching rows from the other table, but only if there are matching rows in the other table.Which type of join you use will depend on the specific needs of your query. However, by avoiding outer joins, you can improve the performance of your query and make it easier to work with the data.
Avoiding outer joins can also help to improve the security of your database. By only returning rows that have matching values in both tables, you can reduce the risk of unauthorized access to sensitive data.