INSTR and SUBQUERY

Question

Hello
I have to statements here that I don't understand. Can anyone explain what these two statements do.
In the first statement I don't know what the 3 and 2 is.
INSTR:
SELECT INSTR('CORPORATE FLOOR','OR', 3, 2) "Instring"
FROM DUAL;
SUB-SELECT:
SELECT a.ename, a.sal, a.deptno, b.salavg
FROM emp a, (SELECT deptno, avg(sal) salavg
FROM emp
GROUP BY deptno) b
WHERE a.deptno = b.deptno
AND a.sal > b.salavg;

Answer 1

Hi,
INSTR - gives the starting position of the occurence of the string that is searched for, starting from the given position and if it is of nth occurrence.
INSTR('STRING THAT IS SEARCHED' ,'STRING TO SEARCH',
SEARCH_FROM_POSITION, SEARCH_FOR_Nth_OCCURRENCE)
STRING THAT IS SEARCHED = 'CORPORATE FLOOR'
STRING TO SEARCH = 'OR'
SEARCH_FROM_POSITION = 3 (i.e. from the 3rd char)
SEARCH_FOR_Nth_OCCURRENCE = 2 (i.e. the second time 'OR'
occurrs after the 2nd char)
For the following query would return - 14.
SELECT INSTR('CORPORATE FLOOR','OR', 3, 2) "Instring"
FROM DUAL;
SUBQUERY,
That is not a subquery that you had qiven, it is an inline view. It is nothing but a query in the FROM clause.
Regards,
Bharath