Look up or repair DuckDB SQL syntax and verify MotherDuck-specific command and feature support.

DuckDB SQL Reference for MotherDuck Source Of Truth Prefer current DuckDB SQL docs for language features and function semantics. Use current MotherDuck SQL docs for MotherDuck only commands such as shares, secrets, snapshots, and Dive operations. MotherDuck can lag upstream DuckDB releases for client compatibility; check MotherDuck version lifecycle docs before promising newly released DuckDB syntax or types are available. If the connection path matters, verify behavior against the current Postgres endpoint docs before promising server mode support. Default Posture Write DuckDB SQL, not PostgreSQL SQL, even when the client connects through the Postgres endpoint. Prefer fully qualified "database"."schema"."table" names; they are required once more than one database or share is attached. Prefer DuckDB native constructs when they simplify the query: GROUP BY ALL , QUALIFY , UNION BY NAME , arg max , EXCLUDE , and REPLACE . When porting SQL from another engine, translate functions, date arithmetic, identifier quoting, and type casts explicitly instead of assuming compatibility. Verify current MotherDuck support before relying on recently released upstream DuckDB features such as VARIANT , native GEOMETRY , MERGE INTO , or date trunc return type changes. Check whether the statement depends on local files, extension install/load, temporary table behavior, or other client only features before claiming it will work in MotherDuck. Treat snapshot, restore, and UNDROP DATABASE statements as operational SQL with plan specific retention behavior, not ordinary analytical syntax. Treat INCLUDE PATTERN as whole table/view filtering on a Share. Row filters, hidden columns, and masking use share secure views ( WITH SECURE VIEW ... REPLACES <table AS (SELECT ...) , ALTER SHARE ... ADD DROP SECURE VIEW ), which are unrelated to DuckDB's CREATE SECURE VIEW optimizer barrier. Distinguish physical import ( CREATE DATABASE ... FROM '<file url ' , including a DuckDB file in cloud storage such as 's3://bucket/app.db' ) from zero copy clone sources. Reject filtered shares and shares with secure views as clone sources; use COPY FROM DATABASE instead. Use role/grant SQL for governed access and audit it with SHOW ... statements; do not preserve ACCESS ORGANIZATION as the preferred RBAC pattern. Treat MotherDuck SQL as an additional surface on top of DuckDB SQL, not a replacement for it. MotherDuck adds SQL AI functions: prompt() for generated or structured text, embedding() for vectors, and prompt jev() for typed classification, scoring, yes/no probabilities, and image bounding boxes. See motherduck query for usage and cost rules. Workflow 1. Confirm the connection path and whether the question is about syntax, feature support, or a specific error. 2. Write or repair the statement in DuckDB SQL first. 3. Verify any MotherDuck only command or server mode limitation against the current docs. 4. If the user needs exact syntax or function details, open references/SYNTAX REFERENCE.md . References Read only the reference sections needed for the current task. Read references/SYNTAX REFERENCE.md for DuckDB data types, friendly SQL features, functions, complex types, and common MotherDuck specific gotchas. Related Skills Load related skills only for missing capabilities; reuse established context. motherduck query for writing and validating analytical SQL against live MotherDuck data motherduck connect when syntax support depends on PG endpoint versus native DuckDB behavior motherduck explore when the problem is really missing schema context rather than missing syntax knowledge

motherduck-duckdb-sql