> ## Documentation Index > Fetch the complete documentation index at: https://docs.cockroachlabs.com/llms.txt > Use this file to discover all available pages before exploring further. # Query Data This page has instructions for making SQL [selection queries][selection] against CockroachDB from various programming languages. ## Before you begin Before reading this page, do the following: * [Create a CockroachDB Standard cluster](https://docs.cockroachlabs.com/docs/cockroachcloud/quickstart.md) or [start a local cluster](https://docs.cockroachlabs.com/docs/cockroachcloud/quickstart.md?filters=local). * [Install a Driver or ORM Framework](https://docs.cockroachlabs.com/docs/v24.2/install-client-drivers). * [Connect to the database](https://docs.cockroachlabs.com/docs/v24.2/connect-to-the-database). * [Insert data](https://docs.cockroachlabs.com/docs/v24.2/insert-data) that you now want to run queries against. > [!NOTE] > > When running under the default [`SERIALIZABLE`](https://docs.cockroachlabs.com/docs/v24.2/demo-serializable) isolation level, your application should [use a retry loop to handle transaction retry errors](https://docs.cockroachlabs.com/docs/v24.2/query-behavior-troubleshooting#transaction-retry-errors) that can occur under [contention](https://docs.cockroachlabs.com/docs/v24.2/performance-best-practices-overview#understanding-and-avoiding-transaction-contention). ## Simple selects ```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} SELECT id, balance from accounts; ``` For more information about how to use the built-in SQL client, see the [`cockroach sql`](https://docs.cockroachlabs.com/docs/v24.2/cockroach-sql) reference docs. ```go theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} // 'db' is an open database connection rows, err := db.Query("SELECT id, balance FROM accounts") if err != nil { log.Fatal(err) } defer rows.Close() fmt.Println("Initial balances:") for rows.Next() { var id, balance int if err := rows.Scan(&id, &balance); err != nil { log.Fatal(err) } fmt.Printf("%d %d\n", id, balance) } ``` For complete examples, see: * [Build a Go App with CockroachDB](https://docs.cockroachlabs.com/docs/v24.2/build-a-go-app-with-cockroachdb) (pgx) * [Build a Go App with CockroachDB and GORM](https://docs.cockroachlabs.com/docs/v24.2/build-a-go-app-with-cockroachdb) ```java theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} // ds is an org.postgresql.ds.PGSimpleDataSource try (Connection connection = ds.getConnection()) { Statement stmt = connection.createStatement(); ResultSet rs = stmt.executeQuery("SELECT id, balance FROM accounts"); while (rs.next()) { int id = rs.getInt(1); int bal = rs.getInt(2); System.out.printf("ID: %10s\nBalance: %5s\n", id, bal); } rs.close(); } catch (SQLException e) { System.out.printf("sql state = [%s]\ncause = [%s]\nmessage = [%s]\n", e.getSQLState(), e.getCause(), e.getMessage()); } ``` For complete examples, see: * [Build a Java App with CockroachDB](https://docs.cockroachlabs.com/docs/v24.2/build-a-java-app-with-cockroachdb) (JDBC) * [Build a Java App with CockroachDB and Hibernate](https://docs.cockroachlabs.com/docs/v24.2/build-a-java-app-with-cockroachdb-hibernate) ```python theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} # conn is a psycopg2 connection with conn.cursor() as cur: cur.execute("SELECT id, balance FROM accounts") rows = cur.fetchall() for row in rows: print([str(cell) for cell in row]) ``` For complete examples, see: * [Build a Python App with CockroachDB](https://docs.cockroachlabs.com/docs/v24.2/build-a-python-app-with-cockroachdb-psycopg3) (psycopg3) * [Build a Python App with CockroachDB and SQLAlchemy](https://docs.cockroachlabs.com/docs/v24.2/build-a-python-app-with-cockroachdb-sqlalchemy) * [Build a Python App with CockroachDB and Django](https://docs.cockroachlabs.com/docs/v24.2/build-a-python-app-with-cockroachdb-django) * [Build a Python App with CockroachDB and asyncpg](https://docs.cockroachlabs.com/docs/v24.2/build-a-python-app-with-cockroachdb-asyncpg) ## Order results To order the results of a query, use an `ORDER BY` clause. For example: ```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} SELECT * FROM bank ORDER BY balance; ``` ``` id | balance | payload -----+---------+------------------------------------------------------------------------------------------------------- 0 | -500 | initial-dTqnRurXztAPkykhZWvsCmeJkMwRNcJAvTlNbgUEYfagEQJaHmfPsquKZUBOGwpAjPtATpGXFJkrtQCEJODSlmQctvyh 1 | -499 | initial-PCLGABqTvrtRNyhAyOhQdyLfVtCmRykQJSsdwqUFABkPOMQayVEhiAwzZKHpJUiNmVaWYZnReMKfONZvRKbTETaIDccE 2 | -498 | initial-VNfyUJHfCmMeAUoTgoSVvnByDyvpHNPHDfVoNWdXBFQpwMOBgNVtNijyTjmecvFqyeLHlDbIBRrbCzSeiHWSLmWbhIvh 3 | -497 | initial-llflzsVuQYUlfwlyoaqjdwKUNgNFVgvlnINeOUUVyfxyvmOiAelxqkTBfpBBziYVHgQLLEuCazSXmURnXBlCCfsOqeji 4 | -496 | initial-rmGzVVucMqbYnBaccWilErbWvcatqBsWSXvrbxYUUEhmOnccXzvqcsGuMVJNBjmzKErJzEzzfCzNTmLQqhkrDUxdgqDD (5 rows) ``` For reference documentation and more examples, see the [`ORDER BY`](https://docs.cockroachlabs.com/docs/v24.2/order-by) syntax page. ## Limit results To limit the results of a query, use a `LIMIT` clause. For example: ```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} SELECT * FROM bank LIMIT 5; ``` ``` id | balance | payload -----+---------+------------------------------------------------------------------------------------------------------- 0 | 0 | initial-dTqnRurXztAPkykhZWvsCmeJkMwRNcJAvTlNbgUEYfagEQJaHmfPsquKZUBOGwpAjPtATpGXFJkrtQCEJODSlmQctvyh 1 | 0 | initial-PCLGABqTvrtRNyhAyOhQdyLfVtCmRykQJSsdwqUFABkPOMQayVEhiAwzZKHpJUiNmVaWYZnReMKfONZvRKbTETaIDccE 2 | 0 | initial-VNfyUJHfCmMeAUoTgoSVvnByDyvpHNPHDfVoNWdXBFQpwMOBgNVtNijyTjmecvFqyeLHlDbIBRrbCzSeiHWSLmWbhIvh 3 | 0 | initial-llflzsVuQYUlfwlyoaqjdwKUNgNFVgvlnINeOUUVyfxyvmOiAelxqkTBfpBBziYVHgQLLEuCazSXmURnXBlCCfsOqeji 4 | 0 | initial-rmGzVVucMqbYnBaccWilErbWvcatqBsWSXvrbxYUUEhmOnccXzvqcsGuMVJNBjmzKErJzEzzfCzNTmLQqhkrDUxdgqDD (5 rows) ``` For reference documentation and more examples, see the [`LIMIT`/`OFFSET`](https://docs.cockroachlabs.com/docs/v24.2/limit-offset) syntax page. ## Joins The syntax for a [selection query][selection] with a two-way [join][joins] is shown below. ```sql theme={"theme":{"light":"catppuccin-mocha","dark":"catppuccin-mocha"}} SELECT a.col1, b.col1 FROM some_table AS a JOIN some_other_table AS b ON a.id = b.id WHERE a.col2 > 100 AND a.col3 > now() ORDER BY a.col2 DESC LIMIT 25; ``` Join performance can be a big factor in your application's performance. For more information about how to make sure your SQL performs well, see [Optimize Statement Performance][fast]. ## See also Reference information related to this task: * [Selection queries][selection] * [`SELECT`](https://docs.cockroachlabs.com/docs/v24.2/select-clause) * [Joins][joins] * [Paginate through limited results][paginate] * [Transaction Contention](https://docs.cockroachlabs.com/docs/v24.2/performance-best-practices-overview#transaction-contention) Other common tasks: * [Connect to the Database](https://docs.cockroachlabs.com/docs/v24.2/connect-to-the-database) * [Insert Data](https://docs.cockroachlabs.com/docs/v24.2/insert-data) * [Update Data](https://docs.cockroachlabs.com/docs/v24.2/update-data) * [Delete Data](https://docs.cockroachlabs.com/docs/v24.2/delete-data) * [Run Multi-Statement Transactions](https://docs.cockroachlabs.com/docs/v24.2/run-multi-statement-transactions) * [Troubleshoot SQL Statements](https://docs.cockroachlabs.com/docs/v24.2/query-behavior-troubleshooting) * [Optimize Statement Performance][fast] * [Example Apps](https://docs.cockroachlabs.com/docs/v24.2/example-apps) [selection]: https://docs.cockroachlabs.com/docs/v24.2/selection-queries [manual]: https://docs.cockroachlabs.com/docs/v24.2/manual-deployment [orchestrated]: orchestration.html [fast]: https://docs.cockroachlabs.com/docs/v24.2/make-queries-fast [paginate]: https://docs.cockroachlabs.com/docs/v24.2/pagination [joins]: https://docs.cockroachlabs.com/docs/v24.2/joins