Oracle merge into usage example

Oracle merge into usage example

 

Purpose:Merge into solves the problem of using data from Table B and new table A. If table A does not exist, the data from Table B is inserted into Table;

Syntax:

Merge into [your table-name] [rename your table here]

Using ([write your query here]) [rename your query-SQL and using just like a table]

On ([conditional expression here] and [...]...)

When mathed then [here you can execute some update SQL or something else]

When not mathed then [execute something else here! ]

 

 

------- Instance -------

Merge into
Using (select ID, name from B) c
On (A. ID = C. ID)
When matched then update set a. Name = C. Name
When not matched then insert (A. ID, A. Name) values (C. ID, C. Name );

Purpose: Use table B and new table A with the condition A. ID = B. Id. If table A does not have this condition, insert the data.

If your data volume is large, the SQL efficiency is very high.