I assume that the first query was executed successfully in a separate
transaction.
The second query builds a huge intermediate result incrementally.
To understand such queries you might try a toy example first
(e.g. a table of 10 elements and look at the intermediate
results)
Consider a1.seq = 18 then there are 40M-18 combinations
for which a1.seq Hello again kind people. This is an sql self join on TableA which contains a serial primary key
column called 'seq'. The select is limited to less than 400 rows of
output by 'a1.seq<=400'. sql->select a1.*, sum(a2.num)/17 from TableA a1, TableA a2 where
a1.seq<=400 and a1.seq>=17
and a1.seq This select statement results in 384 rows, as expected, with a newly
calculated column for sum(a2.num)/17 which yields a running average of
'num' between any given value for 'seq' and 'seq+17'. This next sql statement is exactly the same as above except the
limitation of 384 rows of output imposed by 'a1.seq<=400' has been
removed. Note that TableA contained 40 million plus rows. sql->select a1.*, sum(a2.num)/17 from TableA a1, TableA a2 where and
a1.seq>=17 and
a1.seq Error: ERROR: GDKload failed: name=14/1457, ext=buns.priv
ERROR: CMDthetajoin: operation failed. Perhaps there is a better way to accomplish a running aggregate on 40
million rows? Thanks.........George -------------------------------------------------------------------------
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