oracle 小数位数

The following example returns the largest integer equal to or less than 15.7:

SELECT FLOOR(15.7) "Floor" FROM DUAL;

     Floor
----------
        15

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The following example rounds a number to one decimal point:

SELECT ROUND(15.193,1) "Round" FROM DUAL;

     Round
----------
      15.2

The following example rounds a number one digit to the left of the decimal point:

SELECT ROUND(15.193,-1) "Round" FROM DUAL;

     Round
----------
        20 

The following examples illustrate the difference between rounding NUMBER and floating-point number values. NUMBER values are rounded up (for positive values), whereas floating-point numbers are rounded toward the nearest even value:

SELECT ROUND(1.5), ROUND(2.5) FROM DUAL;

ROUND(1.5) ROUND(2.5)
---------- ----------
         2          3

SELECT ROUND(1.5f), ROUND(2.5f) FROM DUAL;

ROUND(1.5F) ROUND(2.5F)
----------- -----------
   2.0E+000    2.0E+000

 

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The following examples truncate numbers:

SELECT TRUNC(15.79,1) "Truncate" FROM DUAL;

  Truncate
----------
      15.7

SELECT TRUNC(15.79,-1) "Truncate" FROM DUAL;

  Truncate
----------
        10

 

注：以上内容来自oracle 10g 帮助文档