trunc(DATE '2009-04-13') 返回日期2009-04-13

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语法：TRUNC（date[,fmt]）
D,WQ @1j!ES1} M| j0　　　TRUNC（number[,decimals]）

Select trunc(TO_DATE('24-11-1999 08:00 pm','dd-mm-yyyy hh:mi am')) RESULT From dual

＝　11/24/1999
,jw2@#tX8~,b0select trunc(sysdate,'day') result from dual

＝本周第一天
`"n5S X*y_u5p5a0select trunc(sysdate,'yy') result from dual

＝本年第一天
nTnG:h V z Dy0select trunc(sysdate,'yy')-1 result from dual

＝上年最后一天

select trunc(sysdate,'mm') result from dual

＝本月第一天

select trunc(sysdate,'dd') result from dual

当天

Select trunc(2999.99222,-3) From dual　＝　２０００

Select trunc(2999.99222,1) From dual　＝２９９９．９

Select trunc(2999.99222,2) From dual　＝　２９９９．９９