Columns in XML datasets can sometimes contain HTML markup, such as <img> tags. This is quite common in data from RSS or Atom web feeds. These HTML tags in column data can cause information to be missing from RAQL queries or cause other problems because the tags are incorrectly interpreted.

To overcome these errors, you can have RAQL escape the column content with HTML tags using CDATA sections by using a column alias in the following form:

With a column named title for example, the alias name to escape any HTML markup in the column content would be title__cdata.