Using pivot option in SQL server 2008.

by using decode function

select job, count(job) from emp group by job;

Code
SELECT count(*), job
FROM emp 
GROUP BY job

select last_name,hiredate,to_char(hiredate,'day') day

eg. if use scott/tiger schema:

select ename, TO_CHAR(hiredate, 'DAY') as DAY from emp;

The Replace Function can replace the old substring whose length are not same to the length of new substring. (length of newsub DONT NEED eaqual tolength of oldsub ) But in Translate Function only can...

It is used to replace one string with another string, and
translate used to translate one character to another char.

Check constraints it cant work multiple tables

Constraints and triggers are both used to enforce business rules at the database level. Constraints are primary key, unique key, foreign key, not null contraints etc, while triggers can be defined at the database and table level to do certain tasks depending on data entered

This will work for only highest salary n=1 but not work for 2nd and rest nth salary...
Did you have tried this?

Code
 SELECT * FROM  (SELECT employee_id, salary, dense_rank() OVER ( ORDER BY salary DESC)  r 
  FROM employees) a 
  WHERE a.r =3 ;