An Error Was Encountered

Error Number: 1054

Unknown column 'function.implode' in 'where clause'

SELECT pt_content.contentID, pt_content.contentTitle, pt_content.contentIntro, pt_content_categories.catName, pt_content_categories.catID FROM pt_content, pt_content_categories WHERE pt_content.contentID = function.implode AND pt_content.catID = pt_content_categories.catID