Question

I have the following query which is supposed to be selecting all the articles from Articles_New which are either A) not in ArticlesInCategories_New or B) in it, but do not have the CategoryID = 7, 8, 9, 10, or 11.

By removing the Category != lines, I’ve determined that the problem is (at the least) that Articles_New is not selecting everything from Articles_New that is not in ArticlesInCategories_New. I still don’t really understand GroupBy, but I’ve based off of other questions, I’ve tried GroupBy Articles_New.ArticleID, and that didn’t change anything.

    SELECT 
       DISTINCT Articles_New.ArticleID, 
       DATE_FORMAT(Articles_New.PublicationDate, '%c/%e/%Y') AS ReleaseDate, 
       Articles_New.Title, 
       Articles_New.Type, 
       Articles_New.URL
     FROM 
       Articles_New
        LEFT JOIN ArticlesInCategories_New
            ON ArticlesInCategories_New.ArticleID = Articles_New.ArticleID
     WHERE 
       PublicationDate >= DATE_SUB(CURDATE(), INTERVAL 2 MONTH) AND
       PublicationDate <= CURDATE() AND
       Articles_New.Public = '1'
       AND ArticlesInCategories_New.CategoryID != '7'
       AND ArticlesInCategories_New.CategoryID != '8'
       AND ArticlesInCategories_New.CategoryID != '9'
       AND ArticlesInCategories_New.CategoryID != '10'
       AND ArticlesInCategories_New.CategoryID != '11' 
     ORDER BY 
       Articles_New.PublicationDate DESC,
       Articles_New.ArticleID DESC

Answer 1

You want all rows that are either:
A) not in ArticlesInCategories_New
B) in ArticlesInCategories_New, but do not have CategoryID = 7, 8, 9, 10, or 11.

SELECT DISTINCT 
   Articles_New.ArticleID, 
   DATE_FORMAT(Articles_New.PublicationDate, '%c/%e/%Y') AS ReleaseDate, 
   Articles_New.Title, 
   Articles_New.Type, 
   Articles_New.URL
 FROM 
   Articles_New
    LEFT JOIN ArticlesInCategories_New
        ON ArticlesInCategories_New.ArticleID = Articles_New.ArticleID
 WHERE 
   (
     ArticlesInCategories_New.ArticleID IS NOT NULL AND
     PublicationDate BETWEEN DATE_SUB(CURDATE(), INTERVAL 2 MONTH) AND CURDATE()
     AND Articles_New.Public = '1'
     AND ArticlesInCategories_New.CategoryID NOT IN ('7','8','9','10','11')
   )
   OR 
   (
     ArticlesInCategories_New.ArticleID IS NULL
   )
 ORDER BY 
   Articles_New.PublicationDate DESC,
   Articles_New.ArticleID DESC