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plsql trunc(with date)函数的介绍

（网上有很多荒谬的中文介绍，可以去google看看。）

在pl/sql中，trunc函数返回由指定测量单位截取的时间值。
trunc函数的语法如下：
      trunc(date, [format])
date就是要被截取的时间值。
format是用于截取的测量单位。如果省略的话date将被截取到day的精度。
format参数表：
   unit                                          valid format parameters
   Year                              SYYY,YYYY,YEAR,SYEAR,YYY,YY,Y
   ISO YEAR                                       IYYY,IY,I
   Quarter                                                      Q
   Month                                       MONTH,MON,MM,RM
   Week                                                      WW
   IW                                                            IW
   W                                                             W
   Day                                                      DDD,DD,J
   Start day of week                                 DAY,DY,D
   Hour                                                HH,HH12,HH24
   Minute                                                    MI
例子：
trunc(to_date("22-AUG-03"), "YEAR")      返回‘01-JAN-03’
trunc(to_date("22-AUG-03"), "Q")      返回‘01-JUL-03’
trunc(to_date("22-AUG-03"), "MONTH")      返回‘01-AUG-03’
trunc(to_date("22-AUG-03"), "DDD")      返回‘22-AUG-03’
trunc(to_date("22-AUG-03"), "DAY")      返回‘17-AUG-03’

详情请见http://www.techonthenet.com/oracle/index.php

posted on 2006-04-16 16:20 gyn_tadao 阅读(1686) 评论(1)  编辑 收藏 引用 所属分类: plsql