Re: joins and performances : general question

hello Rick,
it was just a general question
but you are right : most of answers i get are specific to an RDBMS the conclusions of this discussion could be (imo) :

- the maximum performance is achieved throught a good update of the stats
- each sql order has to be tested on every RDBMS you want to use
- data that are retrieved the fastest are the data you do not retrieve ;)

thanks guys for all these answers !
Regards,
Christian

Rick Gebethner wrote in message <383C5003.8B88C037_at_storm.ca>...
>You sent this to a bunch of db newsgroups. What dbms are you running? If
it's a
>good one, nine times out of ten, the optimizer will do a better job of
figuring
>out a good query plan than you will (assuming your stats are up to date).
>
>Rick Gebethner
>
>Christian Bruno wrote:
>
>> hello,
>> it is a very general question :
>>
>> i have to write sql queries using lot of Joins (mainly left outer and
inner
>> joins)
>>
>> is there rule(s) to apply to write these sql orders, having knowledge of
the
>> average number of rows in my tables ? for example : which order to use
for
>> joins in a particular query ? is it better to begin or to end with the
join
>> that retrieves the more rows in the database ? it is better to use INNER
>> joins than LEFT OUTER JOINS ?
>>
>> thanks for any comments or ideas !
>> Regards,
>> Christian
>
Received on Thu Nov 25 1999 - 02:20:41 CST