According to the SQL semantics of merge, such an update operation is ambiguous as it is unclear which source row should be used to update the matched target row. Here is how to get started with the use MERGE into in SQL Server: Start off by identifying the target table which will be used in the logic. Merge Statement can perform all these operations in our main target table when the source table is provided. First, specify the target table (target_table) which you want to update or insert into in the INTO clause.Second, specify the source of data (source_table) to be updated or inserted in the USING clause.Third, specify the search condition upon which the merge operation either updates or inserts in the ON clause. MERGE is very useful when it comes to loading the data warehouse tables, which can be very large and require the specific actions to be taken when the rows are or are not present. Available in: DSQL, PSQL Added in: 2.1 Description: Merges data into a table or view. It was officially introduced in the SQL:2003 standard, and expanded in the SQL:2008 standard. a parenthesized SELECT statement or CTE).Each source record will be used to update one or more target records, insert a new record in the target table, or neither. Rows in the target that match the input data can be deleted or updated as specified, and rows that do not exist in the target can be inserted. The source may a table, view or derived table (i.e. Next identify the source table which will be used in the logic. Letâs examine the MERGE statement in detail:. A MERGE operation can fail if multiple rows of the source dataset match and attempt to update the same rows of the target Delta table. The SQL Merge statement is an official SQL standard (introduced in SQL: 2003 - the 5th version of the SQL standard) that enables UPDATE, INSERT and DELETE statements to be combined into one easy to use statement. A relational database management system uses SQL MERGE (also called upsert) statements to INSERT new records or UPDATE existing records depending on whether condition matches. Inserts, updates, and deletes values in a table based on values in a second table or a subquery. Check out these additional resources: Using MERGE in SQL Server to insert, update and delete at the same time; Resolving the MERGE statement attempted to UPDATE or DELETE the same row more than once error; Using the SQL Server MERGE Statement to Process Type 2 Slowly Changing â¦ MERGE¶. Check out these other T-SQL tips on MSSQLTips.com. MERGE INTO employees e USING (SELECT * FROM hr_records WHERE start_date > ADD_MONTHS(SYSDATE, -1)) h ON (e.id = h.emp_id) WHEN MATCHED THEN UPDATE SET e.address = h.address WHEN NOT MATCHED THEN INSERT (id, address) VALUES (h.emp_id, h.address); ... SQL> The output shows the straight MERGE statement is an order of â¦ MERGE INTO (SELECT * FROM mytable WHERE status='active') old USING (SELECT * FROM newtable) new ON (new.id = old.id) WHEN MATCHED THEN UPDATE SET old.data1=new.data1; Edit It appears that this produces an ORA-00903 in 9iR2. The SQL Server MERGE command is the combination of INSERT, UPDATE and DELETE commands consolidated into a single statement. The MERGE statement updates a target (a table or view) using data from a source (the result of a table reference or the specified input data). As I wrote while exploring A Hazard of Using the SQL Merge Statement, I love MERGE because I think it is the greatest thing to happen to SQL querying since â¦ This can be useful if the second table is a change log that contains new rows (to be inserted), modified rows (to be updated), and/or marked rows (to be deleted) in the target table. SQL Merge Statement. See the following syntax.