Using UPSERT Operations

INSERT INTO customers (email, full_name)
VALUES ('alice@example.com', 'Alice')
ON CONFLICT (email) DO NOTHING;

INSERT INTO customers (email, full_name, updated_at)
VALUES ('alice@example.com', 'Alice W.', now())
ON CONFLICT (email) DO UPDATE
   SET full_name = excluded.full_name,
       updated_at = excluded.updated_at;

INSERT INTO inventory (sku, qty, updated_at)
VALUES ('A100', 5, now())
ON CONFLICT (sku) DO UPDATE
   SET qty = excluded.qty, updated_at = excluded.updated_at
 WHERE inventory.qty < excluded.qty;     -- only bump if larger

INSERT INTO counters (key, value, updated_at)
VALUES ('hits', 1, now())
ON CONFLICT (key) DO UPDATE
   SET value = counters.value + excluded.value,
       updated_at = excluded.updated_at;

INSERT INTO customers (email, full_name)
VALUES ('alice@example.com', 'Alice')
ON CONFLICT (email) DO UPDATE SET full_name = excluded.full_name
RETURNING id, (xmax = 0) AS was_inserted;

INSERT INTO sessions (id, user_id, last_seen)
VALUES ('abc', 42, now())
ON CONFLICT (id) DO UPDATE SET last_seen = excluded.last_seen;

INSERT INTO daily_stats (date, metric, value)
VALUES (current_date, 'signups', 5)
ON CONFLICT (date, metric) DO UPDATE
   SET value = daily_stats.value + excluded.value;