Using INSTR in PLSQL Query

https://plsqlquery.blogspot.com/2018/05/using-instr-in-plsql-query.html

Finds numeric Position of a named Character

select INSTR('PAKISTAN','I') from dual;
4

select INSTR('PAKISTAN','i') from dual;
0

select INSTR('PAKISTAN','TA') from dual;
6

select INSTR('PAKISTAN','A') from dual;
2

select ENAME , INSTR(ENAME,'K') from EMP;

ENAME                   INSTR(ENAME,'A')
SMITH                     0
ALLEN                    1
WARD                     2
JONES                    0
MARTIN                 2
etc......


Find Occurrence of 'a' Start from 3rd Position

select INSTR('PAKISTAN','A',3) from dual;
7