Lower, upper and initcap are case-conversion functions. If you want to change string, you can use this functions.
Lower : Converts alpha character values to lowercase.
Upper : Converts alpha character values to uppercase.
Inıtcap : Converts alpha character values to uppercase for the first letter of each word, all other letters in lowercase.
Example
Default value for name : FATİH Acar
define name = ‘FATİH Acar’;
select LOWER(name) from dual; Result : fatih acar
select UPPER(name) from dual; Result : FATİH ACAR
select INITCAP(name) from dual; Result : Fatih AcarOther Uses
select * from dual where LOWER(name) like ‘%fatih%’; Result : FATİH Acar
select * from dual where UPPER(name) like ‘%FATİH%’; Result : FATİH Acar
select * from dual where INITCAP(name) like ‘%Fatih%’; Result : FATİH Acar