Hi All,

In Database Documentation I Have seen that the strategy used by database
engine is independent of the order that i put the tables... but... something
is making me feel confused.

That is the situation (a simplified version):

T1 = 10000 Records
T2 = 1000000 Recods

Index on T1.x
Index on T2.x
Index on T2.y

Case 1 :
Select * from T1, T2 where T1.x=T2.x and T2.y = 'AAA'
Srategy used...
1 - Table Scan  T1
2 - Index Seek T2
....

Case 2 : (only changing the order T1, T2)
Select * from T2, T1 where T1.x=T2.x and T2.y = 'AAA'
Srategy used...
1 - Index Seek T2
2 - Index Seek T1
....

Can anyone explain it to me ?

another thing :

Excepting the join clause the rest of where clause is composed dinamicaly by
user... so the user can filter by fields in T1 as in T2 ... so I canot force
the order of tables in select...

Any sugestion ?

Tanks a lot,

Jo�o












-- 
MaxDB Discussion Mailing List
For list archives: http://lists.mysql.com/maxdb
To unsubscribe:    http://lists.mysql.com/[EMAIL PROTECTED]

Reply via email to