如何使SQL查詢結果以2個小數顯示

Question

我偶然遇到了一個問題，使此代碼僅顯示2位小數

SELECT 
SUM(CAST(
Size * 8 as Decimal)/1024
) as [Size in MB]

FROM 
sysfiles

到目前為止，它以7個小數返回了我數據庫的大小：/

Answer 1

我建議轉換為帶有兩個位置的十進制格式：

select convert(decimal(20, 2), size * 8.0/1024) as [Size in MB]
from sysfiles;

這會將值轉換為正確的類型 。 但是，如果要確保該值以正確的精度/小數位顯示，則可以使用format()或str() ：

select str(size * 8.0/1024, 20, 2) as [Size in MB]
from sysfiles;

Answer 2

您可以只使用cast(xxx as decimal({length},{precision}))

SELECT 
SUM(CAST(
Size * 8 as Decimal(20,2))/1024
) as [Size in MB]

FROM 
sysfiles

Answer 3

只是將總和本身轉換為小數

SELECT CAST(SUM(CAST(Size * 8 AS DECIMAL(18,2)) /  1024) AS DECIMAL(18,2)) [Size in MB]