Re: [HACKERS] SQL MERGE patches for PostgreSQL Versions

On Thursday, June 22, 2017 12:32:14 PM EDT Kang Yuzhe wrote:
> Here is a sample what I did after applying the patch.
> 
> testdb=# BEGIN;
> BEGIN
> testdb=#
> testdb=# MERGE INTO Stock USING Buy ON Stock.item_id = Buy.item_id
> testdb-#  WHEN MATCHED THEN UPDATE SET balance = balance + Buy.volume
> testdb-#  WHEN NOT MATCHED THEN DO NOTHING;
> MERGE 1
> testdb=# SELECT * FROM Stock;
>  item_id | balance
> ---------+---------
>       20 |    1900
>       10 |    3200
> (2 rows)
> 
> testdb=# ROLLBACK;
> ROLLBACK

I am not quite sure what you're trying to achieve, but are you aware that 
pgsql 9.6 introduced the ON CONFLICT clause, which allows you to do the same 
with a different syntax?

https://www.postgresql.org/docs/9.6/static/sql-insert.html

Look for ON CONFLICT.