A data table is a table that displays relationships. These relationships do not have to be numerical. For example, there could be a table that displays provinces in Canada and the most common dog breeds in each province. A data table displaying a relationship or relationships should not be coded as presentational.
Generally, it is best to avoid using layout tables when possible. However, layouts tables are present when an HTML
<table> element is being used solely for visual formatting and relationships are not being displayed. Layout tables must be coded as presentational.
For additional support, the Guided Manual WCAG Audit Tool from Accessible Web includes a step to help you identify the tables on a webpage and determine if they are coded correctly.