The MERGE statement is a single command that combines the ability to update or insert rows into a table by conditionally deriving the rows to be updated or inserted from one or more sources. It is most frequently used in data warehouses to move large amounts of data but its use is not limited to only data warehouse environments. The big value-add this statement provides is that you have a convenient way to combine multiple operations into one. This allows you to avoid issuing multiple INSERT, UPDATE, and DELETE statements. Syntax of Merge statement: MERGE INTO <table_name> USING <table_view_or_query> ON (<condition>) WHEN MATCHED THEN <update_clause> DELETE <where_clause> WHEN NOT MATCHED THEN <insert_clause> [LOG ERRORS <log_errors_clause> <reject limit <integer | unlimited>]; Best example: MERGE INTO dept60_bonuses b USING ( SELECT employee_id , salary , departme...
