# DB Maxcompute SQL

> Generate and review Alibaba Cloud MaxCompute or ODPS SQL. Use when namespace mode, partition scanning, data type editions, write semantics, or transactional-table restrictions affect SQL correctness or cost.

- Skill: `datus-ai/db-maxcompute-sql` (Agent Skill)
- Install (CLI): `npx skillmds@latest add datus-ai/db-maxcompute-sql`
- Raw SKILL.md: https://api.skillmd.com/api/skills/datus-ai/db-maxcompute-sql/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: datus-ai (https://skillmd.com/u/datus-ai)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/datus-ai/db-maxcompute-sql

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# MaxCompute SQL

Generate MaxCompute SQL from the configured datasource context and metadata. MaxCompute is also known as ODPS; its PyODPS SDK and Hive parser fallback do not make it a general Hive or Spark SQL engine.

## Namespaces and identifiers

- MaxCompute has no catalog level. A Datus datasource is bound to one project, so do not generate cross-project access.
- In a two-level project, qualify objects as `project.table`; there is no schema namespace.
- In a schema-enabled project, qualify objects as `project.schema.table`. Use the configured or metadata-provided schema, which defaults to `default` when none is supplied.
- Under the Datus adapter contract, a two-part identifier always means `project.table`, never `schema.table`. Use all three parts when a schema-qualified identifier is needed.
- Do not emit `USE`, `USE SCHEMA`, or `SET odps.namespace.schema` to switch context. The connector supplies the project, schema, and namespace hint for each job.
- Preserve metadata-provided names and quote reserved words or special identifiers with backticks.

## Queries and scan cost

- Add predicates on relevant partition columns when querying partitioned tables. Do not silently enable `odps.sql.allow.fullscan`.
- `LIMIT` restricts returned rows only after the distributed scan; it does not reduce bytes scanned or computing cost.
- By default, a global `ORDER BY` requires a `LIMIT`. Include a business-appropriate limit rather than inventing an unbounded sort override.
- Use MaxCompute functions and syntax. Do not borrow a MySQL, PostgreSQL, Spark, or Hive construct unless MaxCompute supports it.

## Types and expressions

- Projects can use MaxCompute V1, V2, or Hive-compatible data type editions. Follow metadata and explicit project context instead of assuming an edition.
- Prefer explicit `CAST` when type coercion is material to correctness; implicit conversion rules differ between editions.
- The adapter's `hive` parser dialect is a parsing fallback, not evidence that `odps.sql.hive.compatible` is enabled.

## Writes and partitions

- `INSERT INTO` appends; `INSERT OVERWRITE TABLE` replaces the target table or static partition. Keep the `TABLE` keyword for overwrite statements.
- Insert mappings are positional, not name-based. Explicitly order target and source expressions to match the destination schema.
- For a static partition, use constant partition values and omit those partition columns from the `SELECT` list.
- For dynamic partitions, place partition expressions last in the `SELECT` list and in the same order as the dynamic partition declaration.
- Generate `UPDATE` or `DELETE` only when metadata or the user confirms a Transactional or Delta table. Ordinary tables do not support row-level updates or deletes.
- Do not generate `BEGIN`, `START TRANSACTION`, `COMMIT`, `ROLLBACK`, `GRANT`, or `REVOKE`; the adapter rejects them.

## Views and materialized views

- Treat ordinary views as logical definitions.
- MaxCompute materialized views store data and have stricter SQL limitations. In particular, do not use window functions or UDTFs in a materialized-view definition, and do not assume another engine's refresh syntax.

## Avoid dialect leaks

Before returning SQL, reject invented catalog, warehouse, cluster, distribution, storage-engine, or transaction syntax. Do not assume primary keys, row-level mutation, or Hive compatibility when the table metadata and project settings do not establish them.