Join through a lookup table.
SQLite: Use explicit aliases and join keys when enriching records through two relationships.
CREATE TABLE categories (id INTEGER PRIMARY KEY,label VARCHAR(30));
CREATE TABLE products (id INTEGER PRIMARY KEY,category_id INTEGER);
CREATE TABLE lines (id INTEGER PRIMARY KEY,product_id INTEGER,quantity INTEGER);
INSERT INTO categories VALUES (1,'Office');
INSERT INTO products VALUES (10,1);
INSERT INTO lines VALUES (100,10,3);
SELECT l.id,c.label,l.quantity FROM lines l JOIN products p ON p.id=l.product_id JOIN categories c ON c.id=p.category_id;Expected output EXAMPLE
100|Office|3
Details
Requires SQLite 3.40 or later. Run with sqlite3 demo.db in a scratch directory. Result rows below use | between columns, without headers; client display formatting may differ. Use explicit aliases and join keys when enriching records through two relationships. The CREATE and INSERT statements provide all input data. Run the complete example in a fresh scratch database or schema.
Tested on Ubuntu 24.04.5 LTS · · SQLite 3.45.1 · bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3
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. Networking disabled. 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
6430bf4763a6d45ba92f598526f9730f10ff83c6e5c49a6e52123f354c37aff4- Dependencies
- bash 5.2.21-2ubuntu4; coreutils 9.4-3ubuntu6.3
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
100|Office|3
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.