I have a table with questions and answers and sessionid.
Sometimes the same person (sessionid) will answer the same question more than 1 time, and that gets stored in the table.
The qapp_answer table content looks something like this:
Id, SessionID, QNumber, Qanswer
72 11 1 3
73 11 1 4
74 11 2 1
75 11 2 3
76 11 3 1
So, I only want each Qnumber to be displayed one time (so 3 rows in total), and basically just use their latest answer for display (Qanswer).
This is the code so far:
select Qnumber, Qanswer
from qapp_answers
where sessionid = 11
group by QNumber, Qanswer
And it returns 5 rows.
Should be simple, but i havent used SQL for years.
You can basically use ROW_NUMBER() which generates sequential number based on the group specified. The query belows group the records by QNumber and generates sequential number sorted by ID in descending order. The latest ID for every group has the value of 1 so you need to filter out records that has a generated value of 1.
SELECT ID, SessionID, QNumber, Qanswer
FROM
(
SELECT ID, SessionID, QNumber, Qanswer,
ROW_NUMBER() OVER (PARTITION BY QNumber ORDER BY ID Desc) rn
FROM tableName
WHERE SessionID = 11
) a
WHERE a.rn = 1
SQLFiddle Demo
Related
I have table called summary_coins , By ranking of coins I am trying to get an user ranking
I have tried like below
SELECT
user_id,
sum(get_count),
rank() over (order by sum(get_count) asc) as rank
FROM summary_coins
WHERE user_id = 2
GROUP BY user_id
sample data , without user_id = 2 in where I am getting below list
user_id sum rank
44 2 1
13 4 2
57 4 2
47 4 2
11 5 5
2 5 5
My desire out put :
2 5 5
Here I am always getting ranking 1 for user ID 2 , But from list of user it should be rank 5.
You want to apply WHERE user_id = 2 late. RANK OVER is the last thing to happen in your query, but you want to apply the WHERE clause afterwards. In order to do this make your query a subquery you select from:
SELECT user_id, sum_count, rank
FROM
(
SELECT
user_id,
sum(get_count) AS sum_count,
rank() over (order by sum(get_count) asc) as rank
FROM summary_coins
GROUP BY user_id
) all_users
WHERE user_id = 2;
Consider the following table:
ID GroupId Rank
1 1 1
2 1 2
3 1 1
4 2 10
5 2 1
6 3 1
7 4 5
I need an sql (for MS-SQL) select query selecting a single Id for each group with the lowest rank. Each group needs to only return a single ID, even if there are two with the same rank (as 1 and 2 do in the above table). I've tried to select the min value, but the requirement that only one be returned, and the value to be returned is the ID column, is throwing me.
Does anyone know how to do this?
Use row_number():
select t.*
from (select t.*,
row_number() over (partition by groupid order by rank) as seqnum
from t
) t
where seqnum = 1;
I have a table of consecutive ids (integers, 1 ... n), and values (integers), like this:
Input Table:
id value
-- -----
1 1
2 1
3 2
4 3
5 1
6 1
7 1
Going down the table i.e. in order of increasing id, I want to count how many times in a row the same value has been seen consecutively, i.e. the position in a run:
Output Table:
id value position in run
-- ----- ---------------
1 1 1
2 1 2
3 2 1
4 3 1
5 1 1
6 1 2
7 1 3
Any ideas? I've searched for a combination of windowing functions including lead and lag, but can't come up with it. Note that the same value can appear in the value column as part of different runs, so partitioning by value may not help solve this. I'm on Hive 1.2.
One way is to use a difference of row numbers approach to classify consecutive same values into one group. Then a row number function to get the desired positions in each group.
Query to assign groups (Running this will help you understand how the groups are assigned.)
select t.*
,row_number() over(order by id) - row_number() over(partition by value order by id) as rnum_diff
from tbl t
Final Query using row_number to get positions in each group assigned with the above query.
select id,value,row_number() over(partition by value,rnum_diff order by id) as pos_in_grp
from (select t.*
,row_number() over(order by id) - row_number() over(partition by value order by id) as rnum_diff
from tbl t
) t
It's my first question here so I hope I can explain it well enough,
I want to order my data by amount of occurrences in the table.
My table is like this:
id Daynr
1 2
1 4
2 4
2 5
2 6
3 1
4 2
4 5
And I want it to sort it like this:
id Daynr
3 1
1 2
1 4
4 2
4 5
2 4
2 5
2 6
Player #3 has one day in the table, and Player #1 has 2.
My table is named "dayid"
Both id and Daynr are foreign keys, together making it a primary key
I hope this explains my problem enough, Please ask for more information it's my first time here.
Thanks in advance
You can do this by counting the number of times that things occur for each id. Most databases support window functions, so you can do this as:
select id, daynr
from (select t.*, count(*) over (partition by id) as cnt
from table t
) t
order by cnt, id;
You can also express this as a join:
select t.id, t.daynr
from table as t inner join
(select id, count(*) as cnt
from table
group by id
) as tg
on t.id = tg.id
order by tg.cnt, id;
Note that both of these include the id in the order by. That way, if two ids have the same count, all rows for the id will appear together.
I have a single table, where I want to return a list of the MAX(id) GROUPed by another identifier. However I have a third column that, when it meets a certain criteria, "trumps" rows that don't meet that criteria.
Probably easier to explain with an example. Sample table has:
UniqueId (int)
GroupId (int)
IsPriority (bit)
Raw data:
UniqueId GroupId IsPriority
-----------------------------------
1 1 F
2 1 F
3 1 F
4 1 F
5 1 F
6 2 T
7 2 T
8 2 F
9 2 F
10 2 F
So, because no row in groupId 1 has IsPriority set, we return the highest UniqueId (5). Since groupId 2 has rows with IsPriority set, we return the highest UniqueId with that value (7).
So output would be:
5
7
I can think of ways to brute force this, but I am looking to see if I can do this in a single query.
SQL Fiddle Demo
WITH T
AS (SELECT *,
ROW_NUMBER() OVER (PARTITION BY GroupId
ORDER BY IsPriority DESC, UniqueId DESC ) AS RN
FROM YourTable)
SELECT UniqueId,
GroupId,
IsPriority
FROM T
WHERE RN = 1