OracleSQL内置函数大全之二

文章作者 100test 发表时间 2007:03:14 13:50:56
来源 100Test.Com百考试题网

24.ln 返回一个数字的对数值

sql> 0select ln(1),ln(2),ln(2.7182818) from dual.

ln(1) ln(2) ln(2.7182818)

--------- --------- -------------

0 .69314718 .99999999

25.log(n1,n2) 返回一个以n1为底n2的对数

sql> 0select log(2,1),log(2,4) from dual.

log(2,1) log(2,4)

--------- ---------

0 2

26.mod(n1,n2) 返回一个n1除以n2的余数

sql> 0select mod(10,3),mod(3,3),mod(2,3) from dual.

mod(10,3) mod(3,3) mod(2,3)

--------- --------- ---------

1 0 2

27.power 返回n1的n2次方根

sql> 0select 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> 0select 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> 0select 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> 0select sin(1.57079) from dual.

sin(1.57079)

------------

1

31.sigh 返回双曲正弦的值

sql> 0select sin(20),sinh(20) from dual.

sin(20) sinh(20)

--------- ---------

.91294525 242582598

32.sqrt 返回数字n的根

sql> 0select sqrt(64),sqrt(10) from dual.

sqrt(64) sqrt(10)

--------- ---------

8 3.1622777

33.tan 返回数字的正切值

sql> 0select 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> 0select 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> 0select 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> 0select to_char(add_months(to_date(199912,yyyymm),2),yyyymm) from dual.

to_cha

------

200002

sql> 0select 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> 0select 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> 0select 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> 0select months_between(19-12月-1999,19-3月-1999) mon_between from dual.

mon_between

-----------

9

sql>0selectmonths_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> 0select 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> 0select 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> 0select 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> 0select 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> 0select rowid,rowidtochar(rowid),ename from scott.emp.

rowid rowidtochar(rowid) ename

------------------ ------------------ ----------

aaaafkaacaaaaeqaaa aaaafkaacaaaaeqaaa smith

aaaafkaacaaaaeqaab aaaafkaacaaaaeqaab allen

aaaafkaacaaaaeqaac aaaafkaacaaaaeqaac ward

aaaafkaacaaaaeqaad aaaafkaacaaaaeqaad jones

43.convert(c,dset,sset)

将源字符串 sset从一个语言字符集转换到另一个目的dset字符集

sql> 0select convert(strutz,we8hp,f7dec) "conversion" from dual.

conver

------

strutz

44.hextoraw 将一个十六进制构成的字符串转换为二进制

45.rawtohext 将一个二进制构成的字符串转换为十六进制

46.rowidtochar 将rowid数据类型转换为字符类型

47.to_char(date,format)

sql> 0select to_char(sysdate,yyyy/mm/dd hh24:mi:ss) from dual.

to_char(sysdate,yy

-------------------