if we have query with few where condition
select t1.*,t2.*,t3.*,t4.* from table1 t1, table2 t2, table3 t3, table4 t4
t1.ID=t2.ID -> 1st condition
t1.ID=t3.ID -> 2nd condition
t1.ID=t4.ID -> 3rd condition
t4.mydate between '1.1.2009' and '1.6.2009' -> 4th condition
t1.name -> 5th
date -> 6th
this is only example.
and now 1,2,3 and 4 condition running in the same time.