SQL Server Wählen Sie in Join Count

Question

ich die Anzahl der Nachrichten erhalten müssen, es gibt mir

Spalte ‚News.NewsId‘ Fehler ungültig ist in der Auswahlliste, weil sie in einer Aggregatfunktion nicht enthalten ist oder die GROUP BY-Klausel.

select News.NewsId 
     , News.NewsTitle 
     , COUNT(News.NewsId) as Total 
from News inner join NewsCategory on News.NewsId = NewsCategory.NewsId 
where NewsCategory.CategoryId in (Select CategoryId 
            from Category 
            where CategoryName = 'travel' 
            or CategoryName = 'Technology' 
            or CategoryName = 'Sport') 

Answer 1

Verwendung ti wie folgt schreiben:

select News.NewsId, News.NewsTitle, COUNT(News.NewsId) as Total from News group by News.NewsId, News.NewsTitle 
inner join 
NewsCategory 
on News.NewsId = NewsCategory.NewsId where NewsCategory.CategoryId in (Select CategoryId from Category where CategoryName = 'travel' or CategoryName = 'Technology' or CategoryName = 'Sport')'Technology' or CategoryName = 'Sport') 

Du bist du singen Anzahl, die ist, warum Sie durch das Feld zu gruppieren müssen, gehören zu Ihrer count (News.NewsId)

Dieses zeigt für jede Kategorie zählen nach jedem NewSID:

select count(1), a.NewsId, a.NewsTitle,b.category from 
(select NewsId, NewsTitle from tbl_news)as a 


left JOIN 

(select NewsId, categoryid,Category from tbl_category) as b 
on a.newsid = b.newsid GROUP BY a.NewsTitle,b.category 

Answer 2

Sie müssen Gruppe der Spalte NewsId und NewsTitle

select News.NewsId 
     , News.NewsTitle 
     , COUNT(News.NewsId) as Total 
from News inner join NewsCategory on News.NewsId = NewsCategory.NewsId 
where NewsCategory.CategoryId in 
         (Select CategoryId 
         from Category 
         where CategoryName IN ('travel','Technology','Sport')) 
GROUP BY News.NewsId 
     , News.NewsTitle 

Oder Sie können die Abfrage als

select News.NewsId 
     , News.NewsTitle 
     , COUNT(News.NewsId) as Total 
from News 
inner join NewsCategory on News.NewsId = NewsCategory.NewsId 
inner join Category  on Category.CategoryId = NewsCategory.CategoryId 
where Category.CategoryName IN ('travel','Technology','Sport')) 
GROUP BY News.NewsId, News.NewsTitle 

Answer 3

Schreiben Sie einfach diese mit zwei verbindet und ein group by:

select n.NewsId, n.NewsTitle, COUNT(*) as Total 
from News n inner join 
    NewsCategory nc 
    on n.NewsId = nc.NewsId join 
    Category c 
    on nc.CategoryId = c.CategoryId 
where c.CategoryName in ('travel', 'Technology', 'Sport') 
group by n.NewsId, n.NewsTitle;