四捨五入與截斷數值
SQL Server 中級
Ginger Grant
Instructor
在 T-SQL 進行四捨五入
ROUND(number, length [,function])
在 T-SQL 進行四捨五入
SELECT DurationSeconds,
ROUND(DurationSeconds, 0) AS RoundToZero,
ROUND(DurationSeconds, 1) AS RoundToOne
FROM Incidents
+--------------------+------------------+------------------+
|DurationSeconds |RoundToZero |RoundToOne |
+--------------------+------------------+------------------+
|121.6480 |122.0000 |121.6000 |
|170.3976 |170.0000 |170.4000 |
|336.0652 |336.0000 |336.1000 |
...
+--------------------+------------------+------------------+
小數點左側的四捨五入
SELECT DurationSeconds,
ROUND(DurationSeconds, -1) AS RoundToTen,
ROUND(DurationSeconds, -2) AS RoundToHundred
FROM Incidents
+--------------------+------------------+------------------+
|DurationSeconds |RoundToTen |RoundToHundred |
+--------------------+------------------+------------------+
|121.6480 |120.0000 |100.0000 |
|170.3976 |170.0000 |200.0000 |
|336.0652 |340.0000 |300.0000 |
...
+--------------------+------------------+------------------+
截斷數值
截斷
17.85 $\rightarrow$ 17
四捨五入
17.85 $\rightarrow$ 18
用 ROUND() 截斷
當你指定第三個參數時，ROUND() 也能用來做截斷。
ROUND(number, length [,function])
- 第三個參數設為非 0 的數值。
在 T-SQL 進行截斷
SELECT Profit,
ROUND(DurationSeconds, 0) AS RoundingtoWhole,
ROUND(DurationSeconds, 0, 1) AS Truncating
FROM Incidents
+--------------------+------------------+------------------+
|Profit |RoundingtoWhole |Truncating |
+--------------------+------------------+------------------+
|15.6100 |16.0000 |15.0000 |
|13.2444 |13.0000 |13.0000 |
|17.9260 |18.0000 |17.0000 |
...
+--------------------+------------------+------------------+
截斷會在指定位數之後直接切掉所有數字。
一起來練習吧！
SQL Server 中級
