週ごとに合計を得るSQLクエリ

Question

神経科医のための医療データを得るためにレポートを作成する必要があります。次のクエリは合計と平均を月単位で取得します。週ごとに総計と平均を引き出すにはどうすればいいですか？

SELECT 
    [Month] = DATENAME(MONTH, DATEADD(MONTH, MONTH(HeadacheDate), -1)), 
    [Total] = COUNT(CASE 
    WHEN Severity > 0 THEN 1 
    END), 
    [Light] = COUNT(CASE 
    WHEN Severity > 0 AND 
     Severity < 4 THEN 1 
    END), 
    [Moderate] = COUNT(CASE 
    WHEN Severity > 3 AND 
     Severity < 7 THEN 1 
    END), 
    [Severe] = COUNT(CASE 
    WHEN Severity > 6 THEN 1 
    END), 
    [DHE or ER] = COUNT(CASE 
    WHEN Medication LIKE '%dhe%' THEN 1 
    END) 
FROM HeadacheData 
WHERE YEAR(HeadacheDate) = 2016 
GROUP BY MONTH(HeadacheDate); 

Answer 1

単にDATENAME機能にWEEK代わりのMONTHを使用しても、それによってグループ。

また、クエリのはるかに読みやすいフォーマットが

SELECT 
    [Week]  = DATENAME(WEEK, DATEADD(MONTH, MONTH(HeadacheDate), -1)) 
    ,[Total]  = COUNT(CASE WHEN Severity > 0 THEN 1 END) 
    ,[Light]  = COUNT(CASE WHEN Severity > 0 AND Severity < 4 THEN 1 END) 
    ,[Moderate] = COUNT(CASE WHEN Severity > 3 AND Severity < 7 THEN 1 END) 
    ,[Severe] = COUNT(CASE WHEN Severity > 6 THEN 1 END) 
    ,[DHE or ER] = COUNT(CASE WHEN Medication LIKE '%dhe%' THEN 1 END) 
FROM HeadacheData 
WHERE YEAR(HeadacheDate) = 2016 
GROUP BY DATENAME(WEEK, DATEADD(MONTH, MONTH(HeadacheDate), -1)); 

...ようなものになるだろう