Reading data from a dynamic column

Reading data from a dynamic column is not the same as with traditional columns. Without some help from a set of special dynamic columns functions, the standard MariaDB SELECT statements will not understand how to properly read the data stored in a dynamic columns BLOB. They will see it as a BLOB column and treat it like any other BLOB. This recipe introduces and demonstrates the basic functions used when reading a dynamic column.

Getting ready

Complete the Creating tables with dynamic columns recipe and the Inserting, updating, and deleting dynamic column data recipe in this chapter.

How to do it...

1. Launch the mysql command-line client. Connect to our MariaDB server and the test database.

2. Discover the columns in our data:

   SELECT id, COLUMN_LIST(dyn_cols) FROM dyn_example;
   

   The following screenshot displays the columns in our data:

   

3. Read data from our table using the following commands:

   SELECT id,
     COLUMN_GET(dyn_cols, 'name' AS CHAR) AS 'name',
     COLUMN_GET(dyn_cols...