Statement Combine For Free

The MERGE statement in SQL is a very popular clause that can handle inserts, updates, and deletes all in a single transaction without having to write separate logic for each of these.The MERGE statement tries to compare the source table with the target table based on a key field and then do some of the processing.

Runs insert, update, or delete operations on a target table from the results of a join with a source table. For example, synchronize two tables by inserting, updating, or deleting rows in one table based on differences found in the other table. MERGE is currently in preview for Azure Synapse Analytics.

Key learningsuse the keyword UNION to stack datasets without duplicate values.use the keyword UNION ALL to stack datasets with duplicate values.use the keyword INNER JOIN to join two tables together and only get the overlapping values.More items...

First, you specify the target table and the source table in the MERGE clause. Second, the merge_condition determines how the rows from the source table are matched to the rows from the target table. It is similar to the join condition in the join clause.

The MERGE statement basically works as separate INSERT, UPDATE, and DELETE statements all within the same statement. You specify a "Source" record set and a "Target" table and the join between the two.

The MERGE statement was introduced in Oracle 9i to conditionally insert or update data depending on its presence, a process also known as an "upsert". The MERGE statement reduces table scans and can perform the operation in parallel if required.

The MERGE statement in SQL is a very popular clause that can handle inserts, updates, and deletes all in a single transaction without having to write separate logic for each of these.The MERGE statement actually combines the INSERT, UPDATE, and the DELETE operations altogether.