Question { 7325 }

How to find last day of the month in sql query

Answer

select to_char(sysdate, 'day') from dual;

This will print output: tuesday i.e

select last_day(sysdate) from dual;

This will print output: 31-Aug-14

Question { Symphony, 10448 }

How to find only %th Highest Sal

Answer

Ans: select distinct(a.salary) from customers a where &n =
(select count(distinct(b.salary)) from customers b where
a.salary <= b.salary);

It will ask you to enter number in input box which salary
you want to see

Question { HCL, 3760 }

difference between HashMap, Hashset and hashTable?

Answer

HashMap -
1) unsynchronized and unordered
2) Allow one null key , multiple null values


HashTable -
1) synchronized and unordered
2) Doesn't allow null key and value


HashSet -
1) synchronized and ordered
2) Sort elements in ascending order , doesn't allow duplicate elements