# SQL Reference for Lightning Table Queries in Confluent Cloud A Lightning Table query runs read-only SQL on a single Lightning Table. This SQL applies whether you query in the Confluent Cloud Console, through an HTTP API, or with a Model Context Protocol (MCP) client. #### IMPORTANT Lightning Tables are rolling out to Confluent Cloud accounts in phases. If you don’t see this feature, it’s not available for your account at this time. ## Supported SQL capabilities A Lightning Table query supports the following SQL capabilities: - **Key lookups**: Look up rows by primary key value. - **Filters**: Narrow results in the `WHERE` clause by using the following operators: equality (`=`), inequality (`!=`), comparison (`>`, `<`, `>=`, `<=`), set membership (`IN`, `NOT IN`), null checks (`IS NULL`, `IS NOT NULL`), pattern matching (`LIKE`, `NOT LIKE`), and range (`BETWEEN`). - **Compound predicates**: Combine multiple conditions with the `AND` and `OR` operators. - **Column selection**: Select specific columns to reduce the response size, or select all columns. - **Ordering**: Sort results in ascending or descending order with the `ORDER BY` clause. - **Row limits**: Control the number of rows returned with the `LIMIT` clause. ### Example query The following query reads the Lightning Table for the `orders` topic. It returns the 10 most recent orders with more than five units. ```sql SELECT ORDERID, ITEMID, ORDERUNITS FROM `orders` WHERE ORDERUNITS > 5 ORDER BY ORDERTIME DESC LIMIT 10; ``` The query uses the following supported capabilities: - **Column selection**: The `SELECT` clause returns only the `ORDERID`, `ITEMID`, and `ORDERUNITS` columns. - **Filters**: The `WHERE` clause uses the `>` operator to return only orders with more than five units. - **Ordering**: The `ORDER BY` clause sorts the orders by the `ORDERTIME` column, newest first. - **Row limits**: The `LIMIT` clause returns at most 10 rows. ### Topic names If a topic name contains any character other than letters and numbers, enclose it in backticks, as in the statement `SELECT * FROM `web-orders` LIMIT 10;`. Quoted names are case sensitive, but unquoted names aren’t. ### Limits Limits, such as the maximum number of rows a query returns, depend on the query interface. For the limits that apply when you query with MCP, see [Query limits](../../ai/real-time-context-engine/query-data.md#rtce-query-limits). ## Unsupported queries A Lightning Table query is read-only. It doesn’t support the following operations: - Aggregate functions (`COUNT`, `SUM`, `AVG`, `MIN`, `MAX`) - `GROUP BY` clauses - Joins - Subqueries - Set operators (`UNION`, `EXCEPT`, `INTERSECT`) - DDL statements (`CREATE`, `ALTER`, `DROP`) - DML statements (`INSERT`, `UPDATE`, `DELETE`) Confluent Cloud rejects an unsupported query without running it. ## Related content - [Lightning Table Queries in Confluent Cloud](overview.md#lightning-tables-query-overview) - [Manage Lightning Tables in Confluent Cloud](../manage.md#lightning-tables-manage) - [Lightning Tables in Confluent Cloud](../overview.md#lightning-tables-overview) #### NOTE This website includes content developed at the [Apache Software Foundation](https://www.apache.org/) under the terms of the [Apache License v2](https://www.apache.org/licenses/LICENSE-2.0.html).