sqlread error, in Matlab 2018

Error using database.odbc.connection/sqlread (line 174) ODBC Driver Error: [MySQL][ODBC 8.0(a) Driver][mysqld-5.6.38]No database selected

What Can I do?

Answer 1

[Mark Cafaro]

This error will occur if DefaultCatalog is null:

>> conn = database('localmysql', 'root', 'pass');
>> conn.DefaultCatalog

ans =

    'null'

>> sqlread(conn, 'mytable')
Error using database.odbc.connection/sqlread (line 174)
ODBC Driver Error: [MySQL][ODBC 5.3(a) Driver][mysqld-5.7.20-log]No database selected

You either need to set the default database for the data source in ODBC Data Source Administrator, as follows:

1. Open ODBC Data Source Administrator as described at https://docs.microsoft.com/en-us/sql/database-engine/configure-windows/open-the-odbc-data-source-administrator?view=sql-server-2017
2. Double-click on the Data Source you are using in the Data Sources table.
3. Use the dropdown next to the Database label to select a valid default database.
4. Click OK to save the changes.

Or, you need to use the SQL USE statement to switch to a valid database before executing sqlread, as shown:

>> conn.Catalogs

ans =

1×3 cell array

    {'information_schema'}    {'mysql'}    {'performance_schema'}

>> exec(conn, 'USE mysql');
>> sqlread(conn, 'user')

ans =

3×45 table
...