In In the SELECT section of the tutorial, you learned how to select the data from a table, using the <span class="code">*</span> to either select all columns or specify which columns to include by writing out the column headers. This helps you control the width of your table by specifying how many and which columns to include.
In the Filtering section of the tutorial, you learned how to filter which rows to include in your table based on the conditions defined. In this way, you controlled the height of the table by how many and which rows were to be included. Now you have the skills to define which columns and rows (the width and height) from the existing data you want to include in the table you’re creating.
The functions you’ve learned so far are by no means an exhaustive list, but should give you a good starting point for working in SQL on your own. You’ll most likely use many of these going forward, potentially in combination with other more advanced functions.
In the Creating columns section of the tutorial, you’ll work with something new: creating new content to be included in your table. First, you’ll learn how to create your own new columns to be included in the table — typically based on changing existing data into a new form, or by performing calculations based on the existing data.