Need Help on Oracle Select Query - sql

Question

I am finding difficulty to frame a select query.
PFB, for the table and corresponding data:
ID DLS MATCH_STATUS LAST_UPDATE_TIME BO CH FT
1 0 0 09-07-2013 00:00:00 IT TE NA
1 1 1 09-07-2013 00:01:01 IT TE NA
2 0 0 09-07-2013 10:00:00 IP TE NA
3 0 0 09-07-2013 11:00:00 IT YT NA
3 2 2 09-07-2013 11:01:00 IT YT NA
Here
Match_Status 0-->Initial Record
1-->Singel Match
2-->Multi Match
For every record there will be a initial entry with match_status 0 and subsequent matching process end other number such as 1,2 will be update.
I am trying to retrieve records such as total record , waiting match ,single match and multi match group by BO, CH and FT
Below is the expected out put:
BO CH FT TOTAL_RECORD AWAITNG_MATCH SINGLE_MATCH MULTI_MATCH
IT TE NA 1 0 1 0
IP TE NA 1 1 0 0
IT YT NA 1 0 0 2
I have tried below query :
select BO,CH,FT,sum(case when match_status=0 then 1 else 0 end) as TOTAL_RECORD,
sum(case when match_status = 0 then 1 else 0 end) as AWAITING_MATCH,
sum(case when match_status = 1 then 1 else 0 end) as SINGLE_MATCH,
sum(case when match_status = 2 then 1 else 0 end) as MULTI_MATCH from
table1 where last_update_time >= current_timestamp-1
group by BO,CH,FT;
problem with the above query is, awaiting_match is getting populated same as total record as I understand because of match_status=0
Similarly I tried with
select BO,CH,FT,sum(case when match_status=0 then 1 else 0 end) as TOTAL_RECORD,
select (sum(case when t1.ms=0 then 1 else 0 end) from
(select max(match_status) as ms from table1 where last_update_time >= current_timestamp-1 group by id)t1) )awaiting_match,
sum(case when match_status = 1 then 1 else 0 end) as SINGLE_MATCH,
sum(case when match_status = 2 then 1 else 0 end) as MULTI_MATCH from
table1 where last_update_time >= current_timestamp-1
group by BO,CH,FT;
problem with the approach is awaiting_match is getting populated with the same value for subsequent row entry.
Please help me with a suitable query for the desired format.
Thanks a lot in advance.

Answer 1

It seems that you want the last match status. I am guessing that this is actually the maximum of the statuses. If so, the following solves the problem by first grouping on id and then doing the grouping to summarize:
select BO, CH, FT,
count(*) as TOTAL_RECORD,
sum(case when lastms = 0 then 1 else 0 end) as AWAITING_MATCH,
sum(case when lastms = 1 then 1 else 0 end) as SINGLE_MATCH,
sum(case when lastms = 2 then 1 else 0 end) as MULTI_MATCH
from (select id, bo, ch, ft, MAX(match_status) as lastms
from table1
where last_update_time >= current_timestamp-1
group by id, bo, ch, ft
) t
group by BO, CH, FT;
If you actually want the last update to provide the status for the id, then you can use row_number() to enumerate the rows for each id, order by update time descending, and choose the first one:
select BO, CH, FT,
count(*) as TOTAL_RECORD,
sum(case when lastms = 0 then 1 else 0 end) as AWAITING_MATCH,
sum(case when lastms = 1 then 1 else 0 end) as SINGLE_MATCH,
sum(case when lastms = 2 then 1 else 0 end) as MULTI_MATCH
from (select id, bo, ch, ft, match_status,
ROW_NUMBER() over (partition by id order by last_update_time desc) as seqnum
from table1
where last_update_time >= current_timestamp-1
) t
where seqnum = 1
group by BO, CH, FT;