Answer / raj&

materialized views are schema objects that can be used to summarize,precompute,replicate and distribute data.

Answer / nitin

Materialized views are used to precompute a heavy joins instead of executing a joins again n again. Moreover it physically stores the data unlike views where it is conceptually. Materialized views can be refresh on timely manner.

Can you upgrade sql express to full sql?

0 Answers  

---

Can a primary key be a foreign key?

0 Answers  

---

What is the diffrence between IN and EXISTS.which one is faster.

3 Answers   Infogain,

---

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.

4 Answers  

---

What is left join in sql?

0 Answers  

---

what is self join and why is it required? : Sql dba

1 Answers  

---

Can we create non-clustured index on a clustered index ?

4 Answers   TCS,

---

what is global variable in pl/sql

1 Answers  

---

What is sql*loader and what is it used for?

0 Answers  

---

What is pl sql commands?

0 Answers  

---

Explain normalization and what are the advantages of it?

0 Answers  

---

In packages the source code is compiled into p code ? how do we describe the p code

3 Answers  

---