General Advice: Multiple queries VS large joins

I am wondering: I have a database with a few disjoint sets, and I was wondering what people's thoughts and reccomendations are
In general, does it make more sense to make multiple queries on a database, or use large joins (in my case, outer joins)
Is there different scenarios where one approach is better than the other
I have an environment which has both (initially) small to mid - sized data size and rather light accesses to my app. Any suggestions?
Thanks
Andrew WiedIt really depends on way too many factors... how much data is coming from
each side of the join? how many rows are in each table? how effective are
the on and where clauses in limiting results based on an index (or a scan)?
Note that when you run a query against 10,000 rows and then a query against
100,000 rows, your physical I/O will be as much as 110,000. However if you
join these two tables, depending on the above and other factors, your I/O
could be 10,000 * 100,000 (there may be an operation for every row in one
table against every row in the other).
Also remember that if you are using a client to display these results, it
may also be better to stagger the output instead of giving them one big
chunk of data all at once.
--
Aaron Bertrand
SQL Server MVP
http://www.aspfaq.com/
"Andrew Wied" <anonymous@.discussions.microsoft.com> wrote in message
news:4F8067E3-E4C3-4A24-A7E9-705295107956@.microsoft.com...
> I am wondering: I have a database with a few disjoint sets, and I was
wondering what people's thoughts and reccomendations are:
> In general, does it make more sense to make multiple queries on a
database, or use large joins (in my case, outer joins)?
> Is there different scenarios where one approach is better than the
other?
> I have an environment which has both (initially) small to mid - sized data
size and rather light accesses to my app. Any suggestions?
> Thanks!
> Andrew Wied