You can use the NATURAL keyword to indicate that a join should be performed based on all columns that have the same name in the two tables being joined. For example, what titles in BOOK_ORDER match those already in BOOKSHELF? The natural join returned the results as if you had typed in the following: The […]
Read More
The join operation is the most time-consuming operation in SQL Server query processing. Learn more.
Read More
The SQL Server Database Engine sets the maximum number of tables that can be joined in a SELECT statement is 64. Learn more.
Read More
In a three-table join, Oracle joins two of the tables and joins the result with the third table. Learn how Oracle determines which is the driving table in a query.
Read More
Unlike Oracle fast full scans that have a single index satisfying the entire query, INDEX-MERGE joins have multiple indexes satisfying the entire query. Learn how this impacts performance.
Read More
HASH joins in Oracle can be effective when the lack of a useful index renders NESTED LOOPS joins inefficient. Learn more.
Read More
If two row sources being joined are actually tables that are part of a cluster, and if the join is an equijoin between the cluster keys of the two tables, then Oracle can use a CLUSTER join. Learn more.
Read More
In a SORT-MERGE join, Oracle sorts the first row source by its join columns, sorts the second row source by its join columns, and then merges the sorted row sources together. Learn more.
Read More
There are five primary join methods in Oracle, each with a unique set of features and limitations. Answer these 5 questions before you attack a potential join issue.
Read More
Learn how the SQL Server optimizer uses merge joins to improve database performance.
Read More
Learn about the SQL Server hash join and how it can affect performance.
Read More
SQL Server nested loop join are particularly effective if the outer input is small and the inner input is sorted and large. Learn more.
Read More