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Description

Error 1046 indicates that a SQL query or command was issued without an active database context. This typically happens when you attempt to perform operations like creating tables or inserting data without first selecting a specific database to work within, or if the connection itself doesn't specify a default database.

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Error Message

No database selected

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Known Causes

3 known causes

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Database Not Explicitly Selected

The most common cause is attempting to execute DDL or DML statements without first using the `USE database_name;` command in the current session.

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Missing Database in Connection String

The application or client connecting to MariaDB failed to specify a default database within its connection parameters or URI.

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SQL Script Lacks Database Context

Executing a SQL script or batch file that assumes a database is already selected, but the execution environment has not provided one.

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Solutions

3 solutions available

1. Select a Database Explicitly easy

Specify the database to use for your SQL commands.

1

Before executing any SQL statements that operate on tables or other database objects, explicitly select the database you intend to use. You can do this using the `USE` statement.

USE your_database_name;

2

After successfully executing the `USE` statement, you can proceed with your intended SQL commands.

-- Example: Now you can execute queries like this:
SELECT * FROM your_table_name;

2. Specify Database on Connection easy

Provide the database name when connecting to MariaDB.

1

When connecting to your MariaDB server using a client tool (like the `mariadb` command-line client, MySQL Workbench, DBeaver, or through application code), specify the database name as an argument. For the `mariadb` client, use the `-D` option or include it after the hostname.

mariadb -u your_username -p -D your_database_name
# Or:
mariadb -u your_username -p your_database_name

2

If connecting via an application (e.g., Python with `mysql.connector`), ensure the database name is part of the connection parameters.

import mysql.connector

cnx = mysql.connector.connect(
    user='your_username',
    password='your_password',
    host='your_host',
    database='your_database_name'
)

3. Qualify Table Names with Database Name medium

Prefix table names with the database name in your SQL queries.

1

Instead of relying on a `USE` statement or connection-time database selection, you can fully qualify your table names by prefixing them with the database name followed by a dot (`.`). This makes your queries self-contained and less dependent on the current database context.

SELECT * FROM your_database_name.your_table_name;

2

This approach is particularly useful in scripts or applications where you might be interacting with multiple databases and want to ensure clarity and avoid accidental operations on the wrong database.

-- Example for an INSERT statement:
INSERT INTO your_database_name.another_table (column1, column2) VALUES ('value1', 'value2');

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Related Errors

5 related errors

MariaDB Error 1046: No Database Selected