All,

I am reviewing a program which was originally created 10+ years ago.
Some SQL statements which are executed are performing extremely poorly
and I am trying to optimize them.

Accordingly, I'd like some "2nd opinions" about the way I am restating
the statements.

The original statement reads:

select avg(updates.col_decim)
from updates
where
updates.col_key in
(select updates.col_key
from updates, hundred
where hundred.col_key = updates.col_key
and updates.col_decim > 980000000)

My new statement reads:

select avg(updates.col_decim)
from updates
join hundred ON hundred.col_key = updates.col_key
where updates.col_decim > 980000000


I can tell you that they both provide the same answer, for the database
I'm working with.

Does anyone think that the two statements ARE NOT equivalent?


Sean