数値の丸めと切り捨て
中級 SQL Server
Ginger Grant
Instructor
T-SQL での数値の丸め
ROUND(number, length [,function])
T-SQL での数値の丸め
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 |
...
+--------------------+------------------+------------------+
小数点の左側での丸め
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 |
...
+--------------------+------------------+------------------+
数値の切り捨て
切り捨て
17.85 $\rightarrow$ 17
丸め
17.85 $\rightarrow$ 18
ROUND() による切り捨て
ROUND() 関数は、第3引数を指定することで値を切り捨てるためにも使用できます
ROUND(number, length [,function])
- 第3引数にゼロ以外の値を設定します
T-SQL での切り捨て
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 |
...
+--------------------+------------------+------------------+
切り捨ては、指定した桁以降の数値をすべて除去します
練習しましょう！
中級 SQL Server
