ACE test series

Question

EMPLOYEE(Fname,Lname,Eno,Bdate,Address,Sex,Salary,Superssn,dno)

DEPENDENT(Eno,DFname,DLname,age)

Query1 :

Select Lname,Fname 

From employee E,dependent D

Where E.Eno = D.Eno and E.Fname = D.DFname 

 

Query 2 :

Select Lname , Fname 

From employee E

Where exists(Select * From dependent D Where E.Eno = D.Eno and E.Fname = D.DFname)

 

What about the complexity of two queries ?

Are they of same complexity? ( in terms of number of comparisons) 

 

 

 

 

Comments

i didn't hear about this, seems to be correct

But can you provide any resource for this ?

---

@Shaik Masthan

then i have to need one more comparission to print the row-1 of table₁ in the result ( where exist (subquery) ).

∴ Y = X + r  ( one extra comparission for each row )

not getting this one...why one extra comparison? 

---

you have to check, the result exist or not? For a row in table1