Query Data

Warning:
This version of CockroachDB is no longer supported. For more details, see the Release Support Policy.

This page has instructions for making SQL selection queries against CockroachDB from various programming languages.

Before you begin

Before reading this page, do the following:

Note:

Your application should use a retry loop to handle transaction errors that can occur under contention.

Simple selects

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SELECT id, balance from accounts;

For more information about how to use the built-in SQL client, see the cockroach sql reference docs.

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// '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:

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// 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:

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# 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:

Order results

To order the results of a query, use an ORDER BY clause.

For example:

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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 syntax page.

Limit results

To limit the results of a query, use a LIMIT clause.

For example:

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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 syntax page.

Joins

The syntax for a selection query with a two-way join is shown below.

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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 Query Performance.

See also

Reference information related to this task:

Other common tasks:

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