Insert or update on a key conflict.
Use a unique key to update an existing row.
CREATE TABLE settings (key TEXT PRIMARY KEY, value TEXT);
INSERT INTO settings VALUES ('theme', 'light');
INSERT INTO settings VALUES ('theme', 'dark')
ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value
RETURNING key, value;Expected output EXAMPLE
theme|dark
Details
Requires PostgreSQL 18. Run in an empty scratch schema using psql or a SQL client. Result rows below use | between columns, without headers; client display formatting may differ. EXCLUDED refers to the row proposed for insertion. Each example includes its own data and should be run in a fresh scratch schema.
Tested on Ubuntu 24.04.5 LTS · · PostgreSQL 18.6 (Debian 18.6-1.pgdg13+2) · libc6 2.39-0ubuntu8.9; psycopg 3.2.10; pymssql 2.3.8
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Snippet process uid 65534 with a read-only root filesystem and temporary working files. Database services use a private internal Docker network without published ports. Fresh scratch schema/database for each case; test database administrator credentials are confined to these disposable services. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged process) / C.UTF-8
- Interpreter invocation
Execute the exact SQL in a fresh database/schema; serialize result rows with | separators- Container image ID
sha256:ec91410a8f6ec3e985830b5e3a0560306d36f8c1c5ccd91a6699abe707123fa3- Code SHA-256
a18bdf480714c96a197a198f88b4462d2d162a4bef7c1bbfa43af33b4068ef43- Dependencies
- libc6 2.39-0ubuntu8.9; psycopg 3.2.10; pymssql 2.3.8
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
# No input files required.
Observed standard output
theme|dark
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.