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

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://docs.firebolt.io/feedback

```json
{
  "path": "/performance-and-observability/query-planning/query-hints",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

> Influence the planner behavior using hint comments.

# Query hints

Firebolt supports the use of query hints, which are special comments embedded in your SQL statements.
These hints allow you to influence the behavior of the query planner, giving you greater control over how your queries are executed.

Query hints are comments that start with `/*!` and end with `*/`.
The following example demonstrates the syntax using the hint `no_partial_agg`:

```sql SQL source {2} theme={"theme":{"light":"github-light","dark":"github-dark"}}
explain(physical)
select /*! no_partial_agg */
  AVG(quantity),
  location_id
from
  fact_sales
group by
  location_id;
```

## Supported hints in Firebolt

* [**No partial aggregation**.](/performance-and-observability/query-planning/query-hints/no-partial-aggregation)
  Disable partial aggregation for `group by` queries.
* [**No join ordering**.](/performance-and-observability/query-planning/query-hints/no-join-ordering)
  Disable join order optimization and instead use the order of the tables in the query.
* [**Optimize for single row window partitions**.](/performance-and-observability/query-planning/query-hints/optimize-for-single-row-window-partitions)
  Optimize window expressions for high cardinality partitions.
* [**Unique columns**.](/performance-and-observability/query-planning/query-hints/unique-columns)
  Specify that columns contain unique values to improve query optimization.