Help with histogram related query

Question

Hi there,
I'm trying to collect data through a query to draw an histogram. Its between lag count and user count.
Here's my query,
select (Y.lag_range /10) * 10 as range_start,
(((Y.lag_range/10) + 1) * 10) -1 as range_end,
sum(Y.user_count) as user_count
from (
(SELECT ((a.lag )) AS lag_range, COUNT(DISTINCT a.user_id) user_count
FROM testobj a INNER JOIN testobj b
ON a.user_id = b.user_id
GROUP BY ((a.lag) )
)Y
group by ((Y.lag_range /10) * 10), (((Y.lag_range/10) + 1) * 10) -1
The inner query gets the different lag count and user count. The outer query tries to group the lag count in different ranges like 0-9, 10-19, 20-29 and so on.
In my query, the outer query doesnt seem to have any impact and still gives the same answer like the inner one.
I get something like this.
RANGE_START RANGE_END USER_COUNT
0 9 2
1 10 1
2 11 2
3 12 1
when the actual out should be:
RANGE_START RANGE_END USER_COUNT
0 9 6 ( 2 + 1 + 2 + 1)
10 19 6
20 29 5
30 39 4
Could someone tell me what am I missing?
I appreciate any suggestion.
Thanks,

Answer 1

Hi,
Whenever you have a question, you should post a little sample data and the results you want from that data.
MyNewWorld wrote:
I'm trying to collect data through a query to draw an histogram. Its between lag count and user count.
Here's my query,
select (Y.lag_range /10) * 10 as range_start,
(((Y.lag_range/10) + 1) * 10) -1 as range_end,
Could someone tell me what am I missing?You might be missing a call to TRUNC.
(x / 10) * 10is just the same as
xIf you want to round to the next multiple of 10 toward 0, you should say
TRUNC (x / 10) * 10In some languages, dividing one integer by another always returns an integer. SQL is not one of those languages. For example, if you divide 6 by 10 in SQL, the result is .6, and multiplying that by 10 brings you back to 6. <tt>TRUNC (6 / 10)</tt>, however, returns 0 (because 0 is the next integer towards 0 from .6).