Text Functions
DUAL Table
Dual is a special inbuilt table in ORACLE with one row and one column storing “X”. It is generally used to perform calculation , to execute functions with user defined values and display(use ) date functions.
select 2*3 from dual;
select 10+20 from dual;
Lower()
This function helps us to convert / display value of a column or user defined value to lower case.
Select lower(‘COMPUTER’) from dual;
Output:
computer
Select name , lower(name) from std;
Ram ram
MOHAN mohan
To change all the names to lower case in table? And save.
Update std set name=lower(name);
Commit;
Upper()
This function helps us to convert / display value of a column or user defined value to upper case.
Select upper(‘computer’) from dual;
COMPUTER
Select name, upper (name) from STD;
Ram RAM
Mohan kumar MOHAN KUMAR
To convert all the names to upper case in the database.
Update std set name=upper (name);
Commit;
Length()
Helps us to find the length of value of a column or user defined string.
Select name,length(name) from emp;
Ram 3
Mohan 5
Kapil 5
Ram kumar 9
Select length(‘computer’) from dual;
8
Select length(‘hello world’) from dual;
11
Ascii()
Helps us to display ascii value of the specified character. If string is passed as an arguments the ascii value of 1st character is displayed.
Select ascii(‘a’), ascii(‘A’) from dual;
97 65
select ascii(‘a’),ascii(‘abc’) from dual;
97 97
Char()
Helps us to display the character form a specified ascii value
Select char(65),char(90),char(97),char(122) from dual;
A Z a z
