文字列に変換するよりも、日付計算を使用して時間を削除する方がはるかに効率的です。また、特定の文字列の書式設定を最後まで残す方がはるかに効率的です(または、C#でFormat()
)を使用してそれを行う方がはるかに効率的です。
;WITH c AS
(
SELECT m = DATEADD(MONTH, DATEDIFF(MONTH, 0, s.datekey), 0),
e.employeekey, s.totalcost
FROM dbo.factsales AS s
INNER JOIN dbo.dimstore AS st
ON s.storekey = st.storekey
INNER JOIN dimemployee AS e
ON e.employeekey = st.storemanager
WHERE s.datekey >= '20070101' AND s.datekey < '20070106'
),
d AS
(
SELECT m, employeekey, SalesAmount = SUM(totalcost)
FROM c
GROUP BY m, employeekey
)
SELECT
Mjesec = CONVERT(CHAR(7), m, 120),
employeekey,
SalesAmount
FROM d
ORDER BY employeekey;
アプリでフォーマットを実行できる場合は、これを次のように折りたたむことができます。
;WITH c AS
(
SELECT m = DATEADD(MONTH, DATEDIFF(MONTH, 0, s.datekey), 0),
e.employeekey, s.totalcost
FROM dbo.factsales AS s
INNER JOIN dbo.dimstore AS st
ON s.storekey = st.storekey
INNER JOIN dimemployee AS e
ON e.employeekey = st.storemanager
WHERE s.datekey >= '20070101' AND s.datekey < '20070106'
)
SELECT Mjesec = m, employeekey, SalesAmount = SUM(totalcost)
FROM c
GROUP BY m, employeekey
ORDER BY employeekey;
あるいは:
SELECT Mjesec = DATEADD(MONTH, DATEDIFF(MONTH, 0, s.datekey), 0),
e.employeekey, s.totalcost
FROM dbo.factsales AS s
INNER JOIN dbo.dimstore AS st
ON s.storekey = st.storekey
INNER JOIN dimemployee AS e
ON e.employeekey = st.storemanager
WHERE s.datekey >= '20070101' AND s.datekey < '20070106'
GROUP BY DATEADD(MONTH, DATEDIFF(MONTH, s.datekey, 0), 0), e.employeekey
ORDER BY employeekey;