Answer / ajit

SELECT COUNT(Sal), COUNT(Comm)
FROM Emp;

Answer / mahalakshmi s

select case when col1>col2 then 'col1' else 'col2' end, greatest(col1,col2) end from table_name;

Answer / gaurav

select decode( (select sal from emp where empno = 7521) , (select greatest( sal, comm ) from emp where empno = 7521 ), 'sal', 'comm' ) from dual

You can use multiple decode if more number of columns are there.

Answer / ganesh

create table aa_test(
a number,
b number,
c number)
;

select greatest(a,b,c) from aa_test where a=99 ;

Answer / prashanth

user greatedt function.

Ex select greatest(sal,bonus) from emp where emp_id = 1000;

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0 Answers  

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how to check the 3rd max salary from an employee table? One of the queries used is as follows: select sal from emp a where 3=(select count(distinct(sal)) from emp b where a.sal<=b.sal). Here in the sub query "select count(distinct(sal)) from emp b where a.sal<=b.sal" or "select count(distinct(sal)) from emp b where a.sal=b.sal" should reveal the same number of rows is in't it? Can any one here please explain me how is this query working perfectly. However, there is another query to get the 3rd highest of salaries of employees that logic I can understand. Pls find the query below. "select min(salary) from emp where salary in(select distinct top 3 salary from emp order by salary desc)" Please explain me how "select sal from emp a where 3=(select count(distinct(sal)) from emp b where a.sal<=b.sal)" works source:http://www.allinterview.com/showanswers/33264.html. Thanks in advance Regards, Karthik.

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