Multiple clauses in MERGE for Oracle SQL: UPSERT AND DELETE in a single statement

Question

I have the query in the below form:

public static final String CLASS_UPSERT_QUERY = Joiner.on(" ").join(
    "MERGE INTO CLASS USING DUAL ON",
    "(<condition1>)",
    "WHEN MATCHED THEN",
    "UPDATE SET ()",
    "WHEN NOT MATCHED THEN",
    "INSERT () VALUES ()"
);

My doubt is whether it is possible to have multiple conditions in the same statement. I need to upsert based on certain condition and delete the entries on another.

Something on the lines of below:

public static final String CLASS_UPSERT_QUERY = Joiner.on(" ").join(
    "MERGE INTO CLASS USING DUAL ON",
    "(<condition1>)",
    "WHEN MATCHED THEN",
    "UPDATE SET ()",
    "WHEN NOT MATCHED THEN",
    "(",
    "MERGE INTO CLASS USING DUAL ON(<condition2>)",
    "WHEN MATCHED THEN",
    "DELETE ()",
    "WHEN NOT MATCHED THEN",
    "INSERT () VALUES ()",
    ")"
);

Answer 1

If you take out the java part from the question, this seems like a simple Merge statement in Oracle, where you can do either insert or update based on condition as below:

MERGE INTO tgt_tbl a
  USING src_tbl b
    ON (a.id = b.id)
  WHEN MATCHED THEN
    UPDATE SET a.status = b.status
    WHERE  b.status != 'VALID'
  WHEN NOT MATCHED THEN
    INSERT (id, status)
    VALUES (b.id, b.status)
    WHERE  b.status != 'VALID';

Answer 2

I am going to answer based on oracle's point of view.

When to use merge Statement : To select rows from one or more sources for update or insertion into a table or view. Or to combine insert/update/Delete within a single statement.

Syntax:

MERGE
INTO  target_table tgt
USING source_table src
ON  ( src.object_id = tgt.object_id )
WHEN MATCHED
THEN
UPDATE
SET   tgt.object_name = src.object_name,tgt.object_type = src.object_type
WHEN NOT MATCHED
THEN
INSERT ( tgt.object_id
    , tgt.object_name
    , tgt.object_type )
    VALUES ( src.object_id
    , src.object_name
    , src.object_type );

Please provide your tables and the sample data for us to make you better understand the problem. You haven't provided us with any sample data or tables.