---
title: "What the VAST Query Engine doesn't support"
slug: "dev-database-reference-sql-not-supported"
updated: 2026-10-30T18:19:11Z
published: 2026-10-30T18:19:11Z
canonical: "docs.vastdata.com/dev-database-reference-sql-not-supported"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vastdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# What the VAST Query Engine doesn't support

*Applies to VAST Cluster 5.5.*

The VAST Query Engine in VAST Cluster 5.5 supports a defined subset of SQL. This page lists what it refuses, the error you get, and what to do instead. Most of these work in [Trino](/develop/docs/dev-database-integrations-trino) and [Spark](/develop/docs/dev-database-integrations-spark), which read the same tables; see the [engine comparison](/develop/docs/dev-database-reference-sql-engine-comparison).

The errors are shown as the [reference examples](/develop/docs/dev-database-reference-sql-index#what-errors-look-like) print them: the exception class, then the server's message without its request ID.

| Feature | Error | Workaround |
| --- | --- | --- |
| **Joins**: `JOIN` of any kind, a comma join | `InternalError: The operator 'HASH_JOIN' type=32 is currently not supported.` | Query each table and combine the results in your application, or use Trino or Spark. |
| **Subqueries**: `IN (SELECT ...)`, `EXISTS (...)` | `InternalError: The operator 'HASH_JOIN' type=32 is currently not supported.` | Run the subquery first, and put its values in the outer query. |
| **Scalar subqueries**: `WHERE x > (SELECT ...)`; `(SELECT ...)` in the `SELECT` list | `InternalError: The operator 'NESTED_LOOP_JOIN' type=31 is currently not supported.`; in the `SELECT` list, `... 'CROSS_PRODUCT' type=33 ...` | Run the subquery first, and put its value in the outer query as a constant. |
| **`UPDATE ... FROM`** another table | `InternalError: The operator 'HASH_JOIN' type=32 is currently not supported.` | Read the values from the other table, then run one `UPDATE` per value, or update with the Python SDK, Trino or Spark. |
| **Long `IN` lists**: five or more values that aren't consecutive integers, or five or more strings | `InternalError: The operator 'HASH_JOIN' type=32 is currently not supported.` | Write the list as `OR`s on the column: `id = 1 OR id = 3 OR ...`, which is pushed down. Lists of consecutive integers work at any length, and lists of up to four values work. See [IN lists](/develop/docs/dev-database-reference-sql-select#in-lists). |
| **`GROUP BY`**, **`SELECT DISTINCT`** | `InternalError: The operator 'HASH_GROUP_BY' type=9 is currently not supported.` | Group in Trino or Spark, or read the columns with the Python SDK and group them in Arrow (`table.group_by()`). For one group, filter with `WHERE` and aggregate without `GROUP BY`. |
| **`DISTINCT` in an aggregate** (`count(DISTINCT x)`, `sum(DISTINCT x)`), `min()`, `max()` or `any_value()` on `VARCHAR`, and aggregates such as `string_agg()`, `median()`, `arg_max()` | `InternalError: The operator 'UNGROUPED_AGGREGATE' type=8 is currently not supported for this usage.` `list()` fails with the `HASH_GROUP_BY` error. | For a distinct count, `approx_count_distinct(x)`. For a string's length, aggregate an expression such as `min(length(s))`. Otherwise use Trino or Spark. |
| **`ORDER BY` without `LIMIT`** | `InternalError: The operator 'ORDER_BY' type=1 is currently not supported for this usage.` | Add a `LIMIT`, which makes it a top-N query, or sort the result in your application. |
| **Window functions**, except `row_number() OVER ()` | `InternalError: The operator 'WINDOW' type=6 is currently not supported.` (for `OVER (ORDER BY ...)` and `OVER (PARTITION BY ...)`) | `row_number() OVER ()`, with nothing in the parentheses, works. For other window functions, use Trino or Spark, or compute them in your application. |
| **`UNION`, `INTERSECT`, `EXCEPT`** | `InternalError: The operator 'HASH_GROUP_BY' type=9 is currently not supported.` | `UNION ALL` works. Remove duplicates in your application. |
| **`WITH ... AS MATERIALIZED`**, **`WITH RECURSIVE`** | `InternalError: The operator 'CTE_SCAN' type=26 is currently not supported.`; `... 'REC_CTE' type=41 ...` | A plain `WITH` works. |
| **Reservoir sampling** (`TABLESAMPLE RESERVOIR(...)`) | `InternalError: The operator 'RESERVOIR_SAMPLE' type=16 is currently not supported.` | Use `LIMIT`, or sample in your application. |
| **`CREATE TABLE ... AS SELECT`** | `InternalError: Not implemented Error: not supported` | `CREATE TABLE`, then `INSERT INTO ... SELECT` ([CREATE TABLE](/develop/docs/dev-database-reference-sql-create-table)). |
| **Views**: `CREATE [OR REPLACE] VIEW`, and so `DROP VIEW` | `InternalError: internal error: This functionality is not implemented yet (specific message not set)` (status 58). `DROP VIEW` of a view that doesn't exist fails with `Catalog Error: View with name <view> does not exist!` | Keep the query in your application, or create views in Trino or Spark. |
| **Column constraints and defaults**: `NOT NULL`, `PRIMARY KEY`, `UNIQUE`, `CHECK`, `DEFAULT` | `InternalError: internal error: This functionality is not implemented yet (specific message not set)` (status 58) | Check values in your application. `SORT KEY` is the only constraint. |
| **Generated columns** | `InternalError: Cannot create column "<column>": Generated columns are not supported in this version (possibly more generated columns not reported)` | Compute the value in your application or in the `INSERT ... SELECT`. |
| **Changing a column**: `ALTER COLUMN ... SET DATA TYPE`, `SET DEFAULT`; `ADD CONSTRAINT ... PRIMARY KEY` | `InternalError: internal error: This functionality is not implemented yet (specific message not set)` (status 58); for a primary key, `Not implemented Error: BindAlterAddIndex not supported by this catalog` | Add a new column, copy the values with `UPDATE` and a `CAST`, and drop the old column ([ALTER TABLE](/develop/docs/dev-database-reference-sql-alter-table)). |
| **Upserts**: `INSERT OR REPLACE`, `INSERT OR IGNORE`, `ON CONFLICT` | `InternalError: Binder Error: There are no UNIQUE/PRIMARY KEY Indexes that refer to this table, ON CONFLICT is a no-op` | `DELETE` the old rows and `INSERT` the new ones in one transaction (a connection with `autocommit=False`). |
| **`SET`, `RESET`, `SET VARIABLE`, `PRAGMA`** | `InternalError: The operator 'SET' type=69 is currently not supported.` ([profile a query](/develop/docs/dev-database-guides-profile-a-query#what-the-query-engine-doesnt-have)) | Pass settings as ADBC connection options ([search session settings](/develop/docs/dev-vector-search-reference-configuration)). |
| **`PREPARE`**, **`EXECUTE`** | `InternalError: Serialization Error: Unsupported type for deserialization of LogicalOperator!` | Build each statement as a string. |
| **Bound parameters** (`cur.execute(sql, params)`, with `?` or `$1`) | `ProgrammingError: INVALID_STATE: Cannot configure ingestion options on a statement configured for query` (adbc-driver-vastdb 0.0.32) | Put the values in the SQL text, quoting strings yourself. For many rows, use ADBC bulk ingest (`cur.adbc_ingest()`). |
| **`BEGIN`, `COMMIT`, `ROLLBACK`** in SQL | `InternalError: The operator 'TRANSACTION' type=58 is currently not supported.` | Open the connection with `autocommit=False`, and call `conn.commit()` or `conn.rollback()`; or run the SQL in a Python SDK transaction ([SQL reference](/develop/docs/dev-database-reference-sql-index#how-sql-reaches-the-engine)). |
| **Several statements in one request** | `InternalError: query: '<statements>' contains 2 statements, only 1 statement is supported.` | Call `execute()` once per statement. |
| **`EXPLAIN ANALYZE`** | `InternalError: The operator 'EXPLAIN_ANALYZE' type=63 is currently not supported.` ([profile a query](/develop/docs/dev-database-guides-profile-a-query#what-the-query-engine-doesnt-have)) | Use `EXPLAIN` for the plan, and time the query in your client ([EXPLAIN](/develop/docs/dev-database-reference-sql-explain)). |
| **`SHOW TABLES`** without a schema, **`SHOW ALL TABLES`** | An internal error message; for `SHOW ALL TABLES`, `The operator 'ORDER_BY' type=1 is currently not supported for this usage.` | `SHOW TABLES "<bucket>/<schema>"` ([SHOW](/develop/docs/dev-database-reference-sql-show)). |
| **Reading `MAP` columns** | `InternalError: Unsupported column type 'MAP(VARCHAR, INTEGER)' of column '<column>' in 'VAST_SCAN '.` | Select the table's other columns. Read the map column with the Python SDK, Trino or Spark. |
| **Time-zone types**: reading a `TIMESTAMP WITH TIME ZONE` column; creating a `TIME WITH TIME ZONE` column | `InternalError: Unsupported column type 'TIMESTAMP WITH TIME ZONE' of column '<column>' in 'VAST_SCAN '.`; `Binder Error: TIME WITH TIME ZONE type is not supported in table definitions. ...` | Store times as `TIMESTAMP` in UTC ([data types in SQL](/develop/docs/dev-database-reference-sql-data-types)). |
| **Time-zone functions**: `current_date`, `today()`, `timezone()`, `AT TIME ZONE`, `date_trunc()` on a time-zone value, `CAST(now() AS DATE)`, `now() - INTERVAL ...` | For example `InternalError: Catalog Error: Scalar Function with name "current_date" is not in the catalog, but it exists in the icu extension.`, and `Binder Error: No function matches the given name and argument types '-(TIMESTAMP WITH TIME ZONE, INTERVAL)'. ...` | Cast first: `CAST(now() AS TIMESTAMP) - INTERVAL 1 DAY` works, and is pushed down. |
| **Partitioned tables**: any statement on one, and creating one | Refused: the message says the table is partitioned ([data modeling](/develop/docs/dev-database-guides-data-modeling#partitioned-tables)) | Create and use partitioned tables with the Python SDK, Trino or Spark. |
| **Row filters and column masks**: any statement on a table where one applies to you, for any engine | `query_engine is not supported for tables with row_filter=<mask>` ([vector search security](/develop/docs/dev-vector-search-operations-security#which-rules-work-with-vector-search)) | Query the table with Trino. Column allow and deny rules do work in the Query Engine. |
| **Functions that read files**: `read_parquet()`, `read_csv()` | `InternalError: Permission Error: Cannot access file "<path>" - file system operations are disabled by configuration` | [Import the Parquet files](/develop/docs/dev-database-reference-sql-import-parquet) into a table, or read them with the Python SDK. |
| **Writing to a snapshot** | `InternalError: internal error: Access Denied` (status 1) | Snapshots are read-only. Write to the live table. |
| **Fixed-size array columns**, such as `INTEGER[4]` | `Binder Error: ARRAY type is not supported in table definitions. ...` ([vector search SQL](/develop/docs/dev-vector-search-reference-sql#errors-youll-see)) | Use a `VECTOR(...)` column or a list (`INTEGER[]`). |
| **Projection and partition DDL** | There are no such statements ([5.5.0 release notes](/docs-5-5/docs/vast-cluster-5-5-0-release-notes)). | Manage semi-sorted projections and partitions with the [Python SDK](/develop/docs/dev-database-reference-sdk#semi-sorted-projections). |

## Trino and Spark

Trino and Spark run `GROUP BY`, views and partitioned tables on the same VAST DataBase tables, and Trino runs joins; see [Trino](/develop/docs/dev-database-integrations-trino), [Spark](/develop/docs/dev-database-integrations-spark) and the [engine comparison](/develop/docs/dev-database-reference-sql-engine-comparison).