OracleMERGEステートメントをPostgreSQLUPSERTステートメントに移行する

PostgreSQL 9.3にUPSERTステートメントはないと思いますが、これは可能です：

with cte_dual as (
    select
        v_c1 as key,
        v_c2 as pkey,
        v_c3 as wcount,
        v_c4 as dcount
), cte_update as (
    update my_table as a set
        wcount = b.wcount,
        dcount = b.dcount
    from cte_dual as b
    where b.key = a.key and b.pkey = a.pkey
    returning *
)
insert into my_table (key, pkey, wcount, dcount)
select d.key, d.pkey, d.wcount, d.dcount
from cte_dual as d
where not exists (select * from cte_update as u WHERE u.key = d.key and u.pkey = d.pkey)

同様の質問をいくつか読むことができます：

• PostgreSQLでUPSERT（MERGE、INSERT ... ON DUPLICATE UPDATE）する方法
• PostgreSQLでの重複更新時に挿入しますか？