How to convert an outer join select query to merge in oracle?

@muriel.schmidt 

To convert an outer join select query to a merge statement in Oracle, you can follow these steps:

1. Identify the tables involved in the outer join select query.
2. Determine the join condition used in the outer join select query.
3. Rewrite the outer join select query using the MERGE statement syntax.
4. Use the ON clause in the MERGE statement to specify the join condition.
5. Specify the source and target tables in the MERGE statement.
6. Use the WHEN MATCHED and WHEN NOT MATCHED clauses in the MERGE statement to handle the matching and non-matching rows, respectively.
7. Specify the actions to be taken for matched and non-matched rows in the corresponding clauses.

Here is an example illustrating how to convert an outer join select query to a merge statement in Oracle:

Outer join select query:

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SELECT t1.column1, t2.column2
FROM table1 t1
LEFT OUTER JOIN table2 t2
ON t1.id = t2.id;

Equivalent merge statement:

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MERGE INTO table1 t1
USING table2 t2
ON (t1.id = t2.id)
WHEN MATCHED THEN
    UPDATE SET t1.column1 = t2.column2
WHEN NOT MATCHED THEN
    INSERT (column1, column2)
    VALUES (t2.id, t2.column2);

By following these steps, you can convert an outer join select query to a merge statement in Oracle. Remember to test the MERGE statement thoroughly to ensure it behaves as expected and handles the matching and non-matching rows correctly.