how to translate "insert into on conflict" from postgres to h2 merge - sql

Question

I have a JDBC application that uses postgres INSERT INTO / ON CONFLICT to perform an upsert query. We would like to support H2 as well, but H2 uses the MERGE query instead. How would I go about translating the following query into H2's syntax? The H2 code will be in a separate library, which means that it doesn't have to work in both postgres and H2.
INSERT INTO dest_table(id,
field1,
field2,
field3,
field4)
VALUES (?, ?, ?, ?, ?)
on conflict (id) do update
set (field3,field3) = (excluded.field3, excluded.field4)

Answer 1

Of course, as soon as I posted to StackOverflow I figured it out. Here is my solution:
Table setup
drop table if exists characters;
CREATE TABLE characters (
id int not null,
first character varying(50),
last character varying(50));
insert into characters (id, first, last) values ( 1, 'scooby', 'doo' );
insert into characters (id, first, last) values ( 2, 'eric', 'cartman' );
insert into characters (id, first, last) values ( 3, 'luke', 'skywalker' );
select * from characters;
-------------------------
1,scooby,doo
2,eric,cartman
3,luke,skywalker
The update query looks like this (with hardcoded values, but it should work with placeholders as well)
Insert (no conflict):
merge into characters
using values (4, 'darth', 'vader') as incoming(id,first,last)
on characters.id = incoming.id
when not matched then
insert (id, first, last) values (incoming.id, incoming.first, incoming.last)
when matched then
update set first = incoming.first, last = incoming.last;
select * from characters;
-------------------------
1,scooby,doo
2,eric,cartman
3,luke,skywalker
4,darth,vader
Update (conflict on 'id', just updates darth vader to anikan skywalker):
merge into characters
using values (4, 'anikan', 'skywalker') as incoming(id,first,last)
on characters.id = incoming.id
when not matched then
insert (id, first, last) values (incoming.id, incoming.first, incoming.last)
when matched then
update set first = incoming.first, last = incoming.last;
select * from characters;
-------------------------
1,scooby,doo
2,eric,cartman
3,luke,skywalker
4,anikan,skywalker