Re: SQL Hints

user72_at_go2.pl (Marek Babski) wrote in message news:<11d263ba.0403241212.7ec79596_at_posting.google.com>...
> > Have a look at:
> > http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96533/hintsref.htm#8326
>
> Your link is realy use useful but I still don't understand how works
> methods which optimizer choose for execution - for example:
> SELECT accounts.balance, customers.last_name, customers.first_name
> FROM accounts, customers
> WHERE accounts.customer_id = customers.customer_id;
>
> the optimizer chooses either (1) a nested loops operation, (2) a
> sort-merge operation, or (3) a hash operation to join these tables
>
> How in short description works (1),(2),(3). Particulary I have no
> idea about differences between (1) and (3) ??? (but also (2) is not
> clear for me)

Did you also cram for exams in college?

Some suggestions:
1. in the interview, if you are asked a question and you do not know the answer, then answer "I don't know."

 If you don't know something and admit it, you have a better chance at the job than if you try to talk BS. If you try to claim to know something that you don't and get caught, you burn your chance at that job and possibly others in the future. (Do you think managers at different companies never talk? Do you think all managers stay at the same Company for their whole career?)

2. take some time to read the ORACLE documentation, and in this case there are some good books on ORACLE optimization.

I prefer to work with folks who know their stuff and are willing to learn more. Taking some initiative to learn on your own shows greater potential than answering specific trivia type questions. Fact is, with optimization, you really need to spend a lot of time with the data.

  Good luck!
 (you are going to need it)
  ed Received on Wed Mar 31 2004 - 14:13:47 CST