Impala selects the database

Once connected to Impala, you need to select one from the available databases. I mpala's USE DATABASE statement is used to switch the current session to another database.

Grammar

The following is the syntax of the USE statement.

USE db_name;

Cases

The following is an example of a USE statement. F irst, let's create a database called sample_database, as shown below.

> CREATE DATABASE IF NOT EXISTS sample_database;

This creates a new database and gives you the following output.

Query: create DATABASE IF NOT EXISTS my_db2

Fetched 0 row(s) in 2.73s

If you use the SHOW DATABASES statement to validate the database list, you can observe the name of the newly created database in it.

> SHOW DATABASES;

Query: show DATABASES 
+-----------------------+ 
| name                  | 
+-----------------------+ 
| _impala_builtins      | 
| default               | 
| my_db                 | 
| sample_database       | 
+-----------------------+ 
Fetched 4 row(s) in 0.11s

Now let's use theUSE statement to switch the session to the newly created database (sample_database), as shown below.

> USE sample_database;

This changes the current context to sample_database and displays a message like the one shown below.

Query: use sample_database

Use The Hue browser to select the database

On the left side of Impala's query editor, you'll see a drop-down menu, as shown in the screenshot below.

If you click the drop-down menu, you'll find a list of all databases in Impala, as shown below.

Simply select the database that needs to change the current context.