Sort Merge Join
Sort Merge Join is a database query processing algorithm used to combine rows from two or more tables based on a join condition. It works by first sorting the input tables on the join keys and then merging the sorted results to find matching rows efficiently. This method is particularly effective for large datasets where in-memory operations are not feasible, as it minimizes random disk access.
Developers should learn Sort Merge Join when working with database systems that handle large-scale data processing, such as in data warehousing or analytical queries. It is especially useful for equi-joins (joins based on equality) on unsorted data, as it provides predictable performance and can be parallelized in distributed systems like Apache Spark or Hadoop. Use it in scenarios where data does not fit in memory and requires external sorting to optimize join operations.