27.POWER
返回N1的N2次方根
SQL> Select Power(2,10),Power(3,3) From Dual;
POWER(2,10) POWER(3,3)
----------- ----------
1024 27
28.ROUND和TRUNC
按照指定的精度进行舍入
SQL> Select Round(55.5),Round(-55.4),Trunc(55.5),Trunc(-55.5) From Dual;
ROUND(55.5) ROUND(-55.4) TRUNC(55.5) TRUNC(-55.5)
----------- ------------ ----------- ------------
56 -55 55 -55
29.SIGN
取数字N的符号,大于0返回1,小于0返回-1,等于0返回0
SQL> Select Sign(123),Sign(-100),Sign(0) From Dual;
SIGN(123) SIGN(-100) SIGN(0)
--------- ---------- ---------
1 -1 0
30.SIN
返回一个数字的正弦值
SQL> Select Sin(1.57079) From Dual;
SIN(1.57079)
------------
1
31.SIGH
返回双曲正弦的值
SQL> Select Sin(20),Sinh(20) From Dual;
SIN(20) SINH(20)
--------- ---------
.91294525 242582598
32.SQRT
返回数字N的根
SQL> Select Sqrt(64),Sqrt(10) From Dual;
SQRT(64) SQRT(10)
--------- ---------
8 3.1622777
33.TAN
返回数字的正切值
SQL> Select Tan(20),Tan(10) From Dual;
TAN(20) TAN(10)
--------- ---------
2.2371609 .64836083
34.TANH
返回数字N的双曲正切值
SQL> Select Tanh(20),Tan(20) From Dual;
TANH(20) TAN(20)
--------- ---------
1 2.2371609
35.TRUNC
按照指定的精度截取一个数
SQL> Select Trunc(124.1666,-2) Trunc1,Trunc(124.16666,2) From Dual;
TRUNC1 TRUNC(124.16666,2)
--------- ------------------
100 124.16
36.ADD_MONTHS
增加或减去月份
SQL> Select To_char(Add_months(To_date('199912','Yyyymm'),2),'Yyyymm') From Dual;
TO_CHA
------
200002
SQL> Select To_char(Add_months(To_date('199912','Yyyymm'),-2),'Yyyymm') From Dual;
TO_CHA
------
199910
37.LAST_DAY
返回日期的最后一天
SQL> Select To_char(Sysdate,'Yyyy.Mm.Dd'),To_char((Sysdate)+1,'Yyyy.Mm.Dd') From Dual;
TO_CHAR(SY TO_CHAR((S
---------- ----------
2004.05.09 2004.05.10
SQL> Select Last_day(Sysdate) From Dual;
LAST_DAY(S
----------
31-5月 -04
38.MONTHS_BETWEEN(Date2,Date1)
给出Date2-Date1的月份
SQL> Select Months_between('19-12月-1999','19-3月-1999') Mon_between From Dual;
MON_BETWEEN
-----------
9
SQL>Selectmonths_between(To_date('2000.05.20','Yyyy.Mm.Dd'),To_date('2005.05.20','Yyyy.Dd')) Mon_betw From Dual;
MON_BETW
---------
-60
39.NEW_TIME(Date,'This','That')
给出在This时区=Other时区的日期和时间
SQL> Select To_char(Sysdate,'Yyyy.Mm.Dd Hh24:Mi:ss') Bj_time,To_char(New_time
2 (Sysdate,'PDT','GMT'),'Yyyy.Mm.Dd Hh24:Mi:ss') Los_angles From Dual;
BJ_TIME LOS_ANGLES
------------------- -------------------
2004.05.09 11:05:32 2004.05.09 18:05:32
40.NEXT_DAY(Date,'Day')
给出日期Date和星期X之后计算下一个星期的日期
SQL> Select Next_day('18-5月-2001','星期五') Next_day From Dual;
NEXT_DAY
----------
25-5月 -01
41.SYSDATE
用来得到系统的当前日期
SQL> Select To_char(Sysdate,'Dd-Mm-Yyyy Day') From Dual;
TO_CHAR(SYSDATE,'
-----------------
09-05-2004 星期日
Trunc(Date,Fmt)按照给出的要求将日期截断,如果Fmt='Mi'表示保留分,截断秒
SQL> Select To_char(Trunc(Sysdate,'Hh'),'Yyyy.Mm.Dd Hh24:Mi:ss') Hh,
2 To_char(Trunc(Sysdate,'Mi'),'Yyyy.Mm.Dd Hh24:Mi:ss') Hhmm From Dual;
HH HHMM
------------------- -------------------
2004.05.09 11:00:00 2004.05.09 11:17:00
42.CHARTOROWID
将字符数据类型转换为ROWID类型
SQL> Select Rowid,Rowidtochar(Rowid),Ename From Scott.Emp;
ROWID ROWIDTOCHAR(ROWID) ENAME
------------------ ------------------ ----------
AAAAfKAACAAAAEqAAA AAAAfKAACAAAAEqAAA SMITH
AAAAfKAACAAAAEqAAB AAAAfKAACAAAAEqAAB ALLEN
AAAAfKAACAAAAEqAAC AAAAfKAACAAAAEqAAC WARD
AAAAfKAACAAAAEqAAD AAAAfKAACAAAAEqAAD JONE