عندي سؤالين
Write a query that displays the difference between the highest and lowest salaries. Label the
column DIFFERENCE.
من جدول الموظفين
--------------------------------------------

Create a query that displays the employees’ last names and indicates the amounts of their
annual salaries with asterisks. Each asterisk signifies a thousand dollars. Sort the data in
descending order of salary. Label the column EMPLOYEES_AND_THEIR_SALARIES.


دى التمارين اللى موجود فى الماتريل بتاعت 9i

SQL> select ( select max(sal) from emp) - ( select min(sal) from emp) DIFFERENCE 
 2  from dual;

DIFFERENCE
----------
  4200  

SQL> select rpad(ename,15,' ') || lpad(' ' ,(sal/100),'*') EMPLOYEES_AND_THEIR_SALARIES
 2  from emp order by sal desc;

EMPLOYEES_AND_THEIR_SALARIES
---------------------------------------------------------------------------------------
KING		   *************************************************
SCOTT		  *****************************
FORD		   *****************************
JONES		  ****************************
BLAKE		  ***************************
CLARK		  ***********************
ALLEN		  ***************
TURNER		 **************
MILLER		 ************
WARD		   ***********
MARTIN		 ***********
ADAMS		  **********
JAMES		  ********
SMITH		  *******

14 rows selected.

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