Suppose I have a table like the following:
+----+------+---------+
| id | time | message |
+----+------+---------+
| 1 | 10 | x |
| 2 | 12 | y |
| 1 | 13 | z |
| 2 | 14 | x |
| 1 | 15 | y |
+----+------+---------+
I want to write a query that returns the most updated message per id. Here is my query:
WITH tmp AS
(
SELECT *, ROW_NUMBER() OVER (PARTITION BY id ORDER BY time DESC) as rn
FROM ##TempTable
)
SELECT *
FROM tmp
WHERE rn = 1
which returns:
+----+------+---------+----+
| id | time | message | rn |
+----+------+---------+----+
| 1 | 15 | y | 1 |
| 2 | 14 | x | 1 |
+----+------+---------+----+
I want to add a condition that, for a specific id, if I see message "z" then just keep that row no matter what the time is, but if "z" is not among the messages keep the most updated row for that id. So, the desired output is like:
+----+------+---------+----+
| id | time | message | rn |
+----+------+---------+----+
| 1 | 13 | z | ? |
| 2 | 14 | x | 1 |
+----+------+---------+----+
Any idea how I can modify the query?
here is one way:
select * from (
select *, row_number() over (partition by id order by case when message = 'z' then 1 else 0 end desc, time desc ) rn
from data ) t
where rn = 1
db<>fiddle here
Related
I'm new to big query. I need top 3 scores for each group
| Name | Group | Score |
| A | 1 | 100 |
| B | 2 | 80 |
| C | 3 | 101 |
| D | 1 | 53 |
| X | 2 | 8 |
| Y | 3 | 61 |
| Z | 1 | 97 |
| W | 2 | 20 |
Consider below
select * except(pos)
from (
select *, row_number() over(partition by `group` order by score desc) pos
from `project.dataset.table`
)
where pos <= 3
Another option (more BigQuery'ish)
select arr.*
from (
select array_agg(t order by score desc limit 3) arr
from `project.dataset.table` t
group by `group`
) a, a.arr
Let's say I have the following table:
| sku | id | value | count |
|-----|----|-------|-------|
| A | 1 | 1 | 2 |
| A | 1 | 2 | 2 |
| A | 3 | 3 | 3 |
I want to select rows that don't have the same count for the same id. So my desired outcome is:
| sku | id | value | count |
|-----|----|-------|-------|
| A | 3 | 3 | 3 |
I need something that works with Postgres 10
A simple method is window functions:
select t.*
from (select t.*, count(*) over (partition by sku, id) as cnt
from t
) t
where cnt = 1;
This assumes you really mean the sku/id combination.
+----+-------+
| id | value |
+----+-------+
| 1 | A |
| 2 | B |
| 3 | C |
| 4 | D |
| 5 | D |
| 6 | D |
| 7 | N |
| 8 | P |
| 9 | P |
+----+-------+
Desired output
+----+-------+---------------------+
| id | value | calc ↓ |
+----+-------+---------------------+
| 1 | A | 1 |
| 2 | B | 2 |
| 3 | C | 3 |
| 4 | D | 6 |
| 5 | D | 6 |
| 6 | D | 6 |
| 7 | N | 7 |
| 8 | P | 9 |
| 9 | P | 9 |
| 10 | D | 11 |
| 11 | D | 11 |
| 12 | Z | 12 |
+----+-------+---------------------+
Can you help me for a solution for this ? Id is identity, id must be present in output, must have the same 9 rows in output.
New note: I added rows 10,11,12. Notice that id 10 and 11 which has letter 'D' is in a different group from id 4,5,6
thanks
If the grouping also depends on the surrounding ids then this turns into something like the gaps and islands problem https://www.red-gate.com/simple-talk/sql/t-sql-programming/the-sql-of-gaps-and-islands-in-sequences/#:~:text=The%20SQL%20of%20Gaps%20and%20Islands%20in%20Sequences,...%204%20Performance%20Comparison%20of%20Gaps%20Solutions.%20
You could use the Tabibitosan method https://rwijk.blogspot.com/2014/01/tabibitosan.html
Here you also need to group by your value column but that doesn't complicate it too much:
select id, value, max(id) over (partition by value, island) calc
from (
select id, value, id - row_number() over(partition by value order by id) island
from my_table
) as sq
order by id;
The id - row_number() over(partition by value order by id) expression gives you a number which changes each time the ID value changes by more than 1 for each value of value. This gets included in the max(id) over (partition by value, island) expression. The island number is only valid for that particular value. In your case, both values N and D have a computed island number of 6 but they need to be considered differently.
Db-fiddle https://www.db-fiddle.com/f/jahP7T6xBt3cpbLRhZZdQG/1
For this sample date you need MAX() window function:
SELECT id, value,
MAX(id) OVER (PARTITION BY value) calc
FROM tablename
SELECT id, value, (SELECT max(id) FROM TABLE inner where inner.value = outer.value)
FROM table as outer
I have a table which has multiple records for the same id. Looks like this, and the rows are sorted by sequence number.
+----+--------+----------+----------+
| id | result | duration | sequence |
+----+--------+----------+----------+
| 1 | 12 | 7254 | 1 |
+----+--------+----------+----------+
| 1 | 12 | 2333 | 2 |
+----+--------+----------+----------+
| 1 | 11 | 1000 | 3 |
+----+--------+----------+----------+
| 1 | 6 | 5 | 4 |
+----+--------+----------+----------+
| 1 | 3 | 20 | 5 |
+----+--------+----------+----------+
| 2 | 1 | 230 | 1 |
+----+--------+----------+----------+
| 2 | 9 | 10 | 2 |
+----+--------+----------+----------+
| 2 | 6 | 0 | 3 |
+----+--------+----------+----------+
| 2 | 1 | 5 | 4 |
+----+--------+----------+----------+
| 2 | 12 | 3 | 5 |
+----+--------+----------+----------+
E.g. for id=1, i would like to sum the duration for all the rows before and include result=6, which is 7254+2333+1000+5. Same for id =2, it would be 230+10+0. Anything after the row where result=6 will be left out.
My expected output:
+----+----------+
| id | duration |
+----+----------+
| 1 | 10592 |
+----+----------+
| 2 | 240 |
+----+----------+
The sequence has to be in ascending order.
I'm not sure how I can do this in sql.
Thank you in advance!
I think you want:
select t2.id, sum(t2.duration)
from t
where t.sequence <= (select t2.sequence
from t t2
where t2.id = t.id and t2.result = 6
);
In PrestoDB, I would recommend window functions:
select id, sum(duration)
from (select t.*,
min(case when result = 6 then sequence end) over (partition by id) as sequence_6
from t
) t
where sequence <= sequence_6;
You can use a simple aggregate query with a condition that uses a subquery to recover the sequence corresponding to the record whose sequence is 6 :
SELECT t.id, SUM(t.duration) total_duration
FROM mytable t
WHERE t.sequence <= (
SELECT sequence
FROM mytable
WHERE id = t.id AND result = 6
)
GROUP BY t.id
This demo on DB Fiddle with your test data returns :
| id | total_duration |
| --- | -------------- |
| 1 | 10592 |
| 2 | 240 |
Basic group by query should solve your issue
select
id,
sum(duration) duration
from t
group by id
for the certain rows:
select
id,
sum(duration) duration
from t
where id = 1
group by id
if you want to include it in your result set
select id, duration, sequence from t
union all
select
id,
sum(duration) duration
null sequence
from t
group by id
id | name | value | time |
--------------------------
1 | A | 1 | 1 |
2 | B | 2 | 2 |
3 | C | 2 | 3 |
4 | A | 3 | 3 |
5 | A | 4 | 2 |
and I expected the result as below:
name | value |
--------------
A | 3 |
B | 2 |
C | 2 |
The results are to show name and value which are lastest time and not duplicate with name.
And I try to query:
SELECT name,First(value)
FROM
(SELECT name,value,time
FROM test
ORDER BY time DESC
)
GROUP BY name;
But I got this result:
name | value |
--------------
A | 1 |
B | 2 |
C | 2 |
I don't understand why A value isn't 3 because from subselect I got A values are 3,4,1 respectively.
Query:
SQLFIDDLEExample
SELECT t.name,
(SELECT t1.value
FROM test t1
WHERE t1.name = t.name
ORDER BY t1.time DESC
LIMIT 1) AS value
FROM test t
GROUP BY t.name
Result:
| NAME | VALUE |
----------------
| A | 3 |
| B | 2 |
| C | 2 |
also you can use partitionby
;with cte as (
select id, row_number() over (order by time desc) rn
from test
)
select * from test
join cte on test.id = cte.id and rn = 1
just choose the one which is faster