The advantage of the latter is that repeated references to the subquery may be more efficient as the data is easily retrieved. The Oracle MERGE statement selects data from one or more source tables and updates or inserts it into a target table. The WITH clause may be processed as an inline view or resolved as a temporary table. It is introduced in Oracle 9i version and it supports 9i or later version. Merge statement allows us to make condition-based insert or update into a target table. Improve Your SQL Skills with this FREE course. The WITH clause, or subquery factoring clause, is part of the SQL-99 standard and was added into the Oracle SQL syntax in Oracle 9.2. An Oracle MERGE statement is used to pull data from the source table (s) and update or insert into the target table based on condition. Highlights include:Ģ1:40 - Getting the INSERT vs UPDATE split for merged rowsĢ2:30 - Using triggers to record INSERT vs UPDATEĢ5:00 - INSERT vs UPDATE count Flashback versions queryĢ7:10 - INSERT vs UPDATE count with SQL Monitoringģ3:35 - ORA-30926 unable to get a stable set of rows errorĤ1:10 - Deleting rows in the target missing from the sourceĤ3:20 - Demo of insert vs update count, ORA-30926 error and deleting missingĥ7:50 - Demo of update only MERGE performance compared to UPDATEs This session covered the details of how this works. This session covered the details of how this works. The MERGE statement enables you to do both actions in one SQL statement. ACE Director Alum Daniel Morgan, founder of Morgans Library, is scheduling complimentary technical Workshops on Database Security for the first 30 Oracle. The MERGE statement enables you to do both actions in one SQL statement. This can lead to complex statements and conditional logic. ORA-00001 on merge, concurent transactions When having two simultaneous merges into a table with a unique constraint in different sessions, the second one throws ORA-00001. So you need "update if exists, insert if not exists" logic, aka UPSERT. The Oracle MERGE statement selects data from one or more source tables and updates or insert s it into a target table. Often when loading data you want to add new rows and change the existing ones.
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