The JOIN condition doesn't have to be an equality – it can be any condition you want. JOIN doesn't interpret the JOIN condition, it only checks if the rows satisfy the given condition.

In DBMS, a join is a binary operation that allows you to combine a join product and a selection in a single statement. The purpose of creating a join condition is to assist you in combining data from two …

We can then use the external merge sort algorithm to join the sorted tables. Step through the two sorted tables with cursors and emit matching tuples. May need to backtrack depending on the join type.

In practice, the cost of sort-merge join for an equi-join is usually linear to the relation sizes assuming we have a large enough buffer for sorting everything in two passes can even combine the merge phase …

JOIN CHEAT SHEET. With love from Structured Concepts. We do SQL Server development, performance tuning and training. Follow us on sqlsunday.com or strd.co! STRUCTURED CONCEPTS.

JOIN Combine related tables or sets of data on key values All tables (or relations) must have a unique identifier (primary key) Any related tables must contain a copy of the unique identifier (foreign key) …

natural join is the set of tuples of all combinations in R and S that are equal on their common attribute names. It is denoted by ⋈. The outer join operation is an extension of the join operation. It is used to …