SQL compatibility and limitations

Do not assume PostgreSQL (or any other database) behavior from similar syntax. This page is the implementation-derived record.

Implemented#

DDL/DML above; joins incl. lateral; subqueries incl. correlated EXISTS; WITH [RECURSIVE]; set ops; window functions with PARTITION BY/ORDER BY/ROWS|RANGE|GROUPS frames; GROUPING SETS/ROLLUP/CUBE; DISTINCT [ON]; FILTER; JSON operators/constructors/JSON_TABLE; temporal literals/arithmetic/EXTRACT; ON CONFLICT; RETURNING; EXPLAIN [ANALYZE]; COPY … STDIN/STDOUT (wire); SET/SHOW/DESCRIBE/USE; sequences + nextval/currval; ENUM/DOMAIN/composite types; pg_catalog/information_schema live rows.

Partial#

• ILIKE parses; case-folding ignored in single-table path (acts as LIKE).
• FOR UPDATE accepted, ignored.
• AND/OR use is-true checks: NULL AND TRUE → false (differs from strict 3VL).
• CREATE FUNCTION/PROCEDURE/TRIGGER/EXTENSION/MATERIALIZED VIEW parse to stubs without execution.
• VACUUM/ANALYZE/REINDEX/LOCK/CLUSTER/REFRESH/LISTEN/NOTIFY parse; mostly no engine effect.
• UPDATE…FROM / COPY unsupported inside explicit transactions.
• LIMIT/OFFSET only integer literal or cast.

Unsupported / not available in v0.1.0#

Foreign-key enforcement, RENAME DATABASE, file COPY, cursors, stored-procedure execution, plpgsql beyond DO/PERFORM/RAISE subset, vector/graph/blob types, multi-region/distributed, continuous aggregates/retention/downsampling, TLS transport (flags exist; handshake declined with tls_mode_not_yet_implemented), binary wire values (text only).

Different behavior worth knowing#

• COUNT(DISTINCT) dedups by to_sql_text (1 ≡ 1.0).
• AVG(int) returns normalized Numeric (PG typing preserved deliberately).
• Server default password is plomid; CLI default password is secret; start.sh default is secret. Always set explicitly.
• No compatibility percentage is claimed. Wire + OID + catalog similarity does not imply semantic compatibility.