Difference in performance between the two queries below

venkagov · New User Joined: 10 Aug 2006 Posts: 6 Location: Chennai

Hi,

Can anyone tell me will there be any difference in performance between the two queries below.

Query 1:

Select A.EMPNO,A.EMPNAME,A.DEPTNO,B.DEPTNAME
FROM EMP A,DEPT B
WHERE A.DEPTNO = B.DEPTNO

I think above query uses cartesian product.

Query 2:

Select A.EMPNO,A.EMPNAME,A.DEPTNO,B.DEPTNAME
FROM EMP A INNER JOIN DEPT B
ON A.DEPTNO = B.DEPTNO

Above query uses join.

Join is better than cartesian product right?

Let me know if I am wrong.

Also please tell me some way of comparing the perfomance of queries.

anamikak · New User Joined: 10 May 2006 Posts: 64 Location: Singapore

query 1 and 2 are just the same. They represent inner join.
query 1 and 2 represent two equivalent syntax for performing inner join. when INNER JOIN is specified, the WHERE keyword is replaced with the ON keyword.

anamikak · New User Joined: 10 May 2006 Posts: 64 Location: Singapore

Also, performance wise there is not going to be any difference.

Anamika

venkagov · New User Joined: 10 Aug 2006 Posts: 6 Location: Chennai

Thanks Anamika.