Querying for Consecutive Rows with Certain Characteristics - sql

Question

I've got a table with the following columns:
id int(10)
user int(10)
winner int(10)
profit double
created datetime
The winner column can be either 0 or 1. I'd like to create a query that returns the maximum number of consecutive winners as ordered by the created datetime column along with the first and last created date as well as the sum of the profit column from that period of consecutive winners.

Answer 1

Here's a possible solution that looks at winning streaks per userid.
select head.userid, head.id, sum(profit), count(*)
from #bingo b
inner join (
select cur.userid, cur.id
from #bingo cur
left join #bingo prev
on cur.userid = prev.userid
and prev.id < cur.id
and not exists(
select *
from #bingo inbetween
where prev.userid = inbetween.userid
and prev.id < inbetween.id
and inbetween.id < cur.id)
where cur.winner = 1
and IsNull(prev.winner,0) = 0
) head
on head.userid = b.userid
and head.id <= b.id
left join (
select cur.userid, cur.id
from #bingo cur
left join #bingo prev
on cur.userid = prev.userid
and prev.id < cur.id
and not exists(
select *
from #bingo inbetween
where prev.userid = inbetween.userid
and prev.id < inbetween.id
and inbetween.id < cur.id)
where cur.winner = 1
and IsNull(prev.winner,0) = 0
) nexthead
on nexthead.userid = b.userid
and head.id < nexthead.id
and nexthead.id <= b.id
where nexthead.id is null
and b.winner = 1
group by head.userid, head.id
The two "heads" subqueries are identical, you could put them in a view or a WITH where those are supported. The "heads" subquery searches for each head of a winning streak; that is, the first win or a win that's preceeded by a loss. I'm assuming your id's increase over time, so I'm not using the Created column.
The query below that searches the corresponding head for every row. A head's id must be smaller or equal to the current row's id, and there must be no other head in between.
After that it's a simple matter of grouping on the head, and summing the profits and counting the rows.

Answer 2

I haven't tested it but maybe this will work.
select first_winner.created, last_winner.created, sum(mid_winner.profit)
from T first_winner
join T last_winner
on first_winner.created <= last_winner.created
and first_winner.winner = 1
and last_winner.winner = 1
and not exists -- no losers in between first_winner and last_winner
(
select * from T loser
where loser.winner = 0
and first_winner.created <= loser.created
and loser.created <= last_winner.created
)
join T mid_winner
on first_winner.created <= mid_winner.created
and mid_winner.created <= last_winner.created
and mid_winner.winner = 1
left join T bef_first_winner -- winner before first winner with no losers in between
on bef_first_winner.winner = 1
and bef_first_winner.created < first_winner.created
and not exists
(
select * from T b_loser
where b_loser.winner = 0
and bef_first_winner.created <= b_loser.created
and b_loser.created <= first_winner.created
)
left join T after_last_winner -- winner after last winner with no losers in between
on after_last_winner.winner = 1
and last_winner.created < after_last_winner.created
and not exists
(
select * from T a_loser
where a_loser.winner = 0
and last_winner.created <= a_loser.created
and a_loser.created <= after_last_winner.created
)
where bef_first_winner.id is null
and after_last_winner.id is null
group by first_winner.created, last_winner.created