I want to delete then insert with single statement using a CTE in Postgres. We could use an explicit transaction and 2 statements, but want to avoid that if possible. I don't know if there will be zero or 1+ rows deleted, so I don't think I can use a single WHERE EXISTS or WHERE NOT EXISTS to ensure that the delete statement in the CTE runs first. Here's something like what I envision:
WITH deletions AS ( DELETE FROM foo WHERE a = 'abc' and b = 2 )INSERT INTO FOO (a, b, c) VALUES ('abc', 2, 'new value')but I need a way to force the CTE to run first. There's no pk on the table that would create issues with attempting to update the same record twice in the same transaction.
