Oracle Fetch random Number

1, randomly fetching records from the tableSelect *  from(Select *  fromStaffOrder  bydbms_random.random)whereRowNum< 4To randomly fetch 3 records from the staff table2, generating random numbersSELECTDbms_random. RANDOM fromDUAL; produce a random number of arbitrary sizeSELECT ABS(MOD (Dbms_random. RANDOM, -)) fromDUAL; Generate a random number within 100SELECTTRUNC ( -+ the*Dbms_random.value) fromdual; Generates a random number between 100~1000SELECTDbms_random.value fromdual; Generates a random number between 0~1SELECTDbms_random.value (Ten, -) fromdual; Generates a random number between 10~20SELECTDbms_random.normal fromdual; The normal function returns a set of numbers that obey a normal distribution. This normal distribution has a standard deviation of 1 and a expected value of 0. The value returned by this function has a%is between-1 and+Between 1 and the%Between-2 and+Between 2 and About%Between-3 and+between 3. 3, generating a random stringSelectDbms_random.string ('P', -) fromdual; The first parameter P represents printable, where the string is made up of any printable character and the second parameter represents the return string length4The ceil (n) function returns the smallest integer greater than or equal to N. Dbms_random. VALUE () is randomly generated (0,1) between the numbers. To generate a two-bit random number, you can dbms_random. VALUE ()* -, this produces (0, -), when a random number is generated (0,Ten), just add 10 to ensure that the number is two. Oracle's PL/SQL provides several ways to generate random numbers and random strings, listed below:1Decimal0 ~ 1)     SelectDbms_random.value fromDual2, a decimal number within the specified range (0 ~  - )     SelectDbms_random.value (0, -) fromDual3, an integer within the specified range (0 ~  - )     SelectTrunc (Dbms_random.value (0, -)) fromDual4, a random number string of length 20SelectSubstrcast(Dbms_random.value as varchar2( -)),3, -) fromDual5, random number of normal distributionSelectDbms_random.normal fromDual6, random stringSelectDbms_random.string (opt, length) fromdual opt values are as follows:'u','U': Uppercase Letters'L','L': Lowercase Letters'a','A': Large, lowercase letters'x','X': Numbers, uppercase letters'P','P': Printable characters7, Random dateSelectTo_date (2454084+TRUNC (Dbms_random. VALUE (0,365)),'J') fromdual The base of the specified date by the following statementSelectTo_char (Sysdate,'J') fromDual8, generate GUIDsSelectSys_guid () fromDual--Create a custom function with a delimiter (-) GUIDCreate or Replace functionMy_guidreturn varchar2 isGUIDvarchar( $); Temp varchar( +);begin    Temp:=Sys_guid (); GUID:=SubstrTemp,1,8)|| '-'         ||SubstrTemp,9,4)|| '-'         ||SubstrTemp, -,4)|| '-'         ||SubstrTemp, -,4)|| '-'         ||SubstrTemp, +, A); returnGUID;End;

Oracle Fetch random Number