On 4/21/06, soni de <[EMAIL PROTECTED]> wrote: > > I don't want to query exactly 81900 rows into set. I just want to fetch 50 > or 100 rows at a time in a decreasing order of stime.(i.e 50 or 100 rows > starting from last to end).
aha! you need to implement a 'sliding window' query. simplest is when you are ordering one field that is unique: 1st 50: select * from t order by k limit 50; 2nd 50: select * from t where k > k1 order by k limit 50: if you are ordering on two fields or on a field that is not unique, you must do: 1st 50: select * from t order by j, k limit 50; 2nd 50: select * from t where j >= j1 and (j > j1 or k > k1) order by j, k limit 50; 3 fields: select * from t where i >= i1 and (i > i1 or j >= j1) and (i > i1 or j > k1 or k > k1) order by i,j,k limit 50; i1,j1,k1 are the values of the 50th record you pulled out of the last query. if this seems a little complicated, either wait for pg 8.2 or get cvs tip and rewrite as: select * from t where (i,j,k) > (i1,j1,k1) order by i,j,k limit 50; ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
