Start Updating columns in oracle

Updating columns in oracle

Even if a row of the target table satisfies the DELETE condition but is not included in the data set from the join defined by the MERGE's ON clause, then it is not deleted.

The only rows affected by the delete clause of the MERGE statement are those rows in the target table that are updated by the merge operation.

This means the DELETE WHERE condition evaluates the updated value, not the original value of the row.

You should use the MERGE statement to select rows from one or more sources for insert or update of one or more tables.