I have this table named Samples. The Date column values are just symbolic date values.
+----+------------+-------+------+
| Id | Product_Id | Price | Date |
+----+------------+-------+------+
| 1 | 1 | 100 | 1 |
| 2 | 2 | 100 | 2 |
| 3 | 3 | 100 | 3 |
| 4 | 1 | 100 | 4 |
| 5 | 2 | 100 | 5 |
| 6 | 3 | 100 | 6 |
...
+----+------------+-------+------+
I want to group by product_id such that I have the 1'th sample in descending date order and a new colomn added with the Price of the 7'th sample row in each product group. If the 7'th row does not exist, then the value should be null.
Example:
+----+------------+-------+------+----------+
| Id | Product_Id | Price | Date | 7thPrice |
+----+------------+-------+------+----------+
| 4 | 1 | 100 | 4 | 120 |
| 5 | 2 | 100 | 5 | 100 |
| 6 | 3 | 100 | 6 | NULL |
+----+------------+-------+------+----------+
I belive I can achieve the table without the '7thPrice' with the following
SELECT * FROM (
SELECT ROW_NUMBER() OVER (PARTITION BY Product_Id ORDER BY date DESC) r, * FROM Samples
) T WHERE T.r = 1
Any suggestions?
You can try something like this. I used your query to create a CTE. Then joined rank1 to rank7.
;with sampleCTE
as
(SELECT ROW_NUMBER() OVER (PARTITION BY Product_Id ORDER BY date DESC) r, * FROM Samples)
select *
from
(select * from samplecte where r = 1) a
left join
(select * from samplecte where r=7) b
on a.product_id = b.product_id
Related
I have a dataset that is similar to this. I need to pick out the most recent metadata (greater execution time = more recent) for a client including the sum of quantities and the latest execution time and meta where the quantity > 0
| Name | Quantity | Metadata | Execution time |
| -------- | ---------|----------|----------------|
| Neil | 1 | [1,3] | 4 |
| James | 1 | [2,18] | 5 |
| Neil | 1 | [4, 1] | 6 |
| Mike | 1 | [5, 42] | 7 |
| James | -1 | Null | 8 |
| Neil | -1 | Null | 9 |
Eg the query needs to return:
| Name | Summed Quantity | Metadata | Execution time |
| -------- | ----------------|----------|----------------|
| James | 0 | [2,18] | 5 |
| Neil | 1 | [4, 1] | 6 |
| Mike | 1 | [5, 42] | 7 |
My query doesn't quite work as it's not returning the sum of the quantities correctly.
SELECT
distinct on (name) name,
(
SELECT
cast(
sum(quantity) as int
)
) as summed_quantity,
meta,
execution_time
FROM
table
where
quantity > 0
group by
name,
meta,
execution_time
order by
name,
execution_time desc;
This query gives a result of
| Name | Summed Quantity | Metadata | Execution time |
| -------- | ----------------|----------|----------------|
| James | 1 | [2,18] | 5 |
| Neil | 1 | [4, 1] | 6 |
| Mike | 1 | [5, 42] | 7 |
ie it's just taking the quantity > 0 from the where and not adding up the quantities in the sub query (i assume because of the distinct clause) I'm unsure how to fix my query to produce the desired output.
This can be achieved using window functions (hence with a single pass of the data)
select
name
, sum_qty
, metadata
, execution_time
from (
select
*
, sum(Quantity) over(partition by name) sum_qty
, row_number() over(partition by name, case when quantity > 0 then 1 else 0 end
order by Execution_time DESC) as rn
from mytable
) d
where rn = 1 and quantity > 0
order by name
result
+-------+---------+----------+----------------+
| name | sum_qty | metadata | execution_time |
+-------+---------+----------+----------------+
| James | 0 | [2,18] | 5 |
| Mike | 1 | [5,42] | 7 |
| Neil | 1 | [4,1] | 6 |
+-------+---------+----------+----------------+
db<>fiddle here
I have three different tables that look like that:
Table 1
| id | city|
|----|-----|
| 1 | A |
| 1 | B |
| 2 | C |
Table 2
| id | city|
|----|-----|
| 2 | B |
| 1 | B |
| 3 | C |
Table 3
| id | city|
|----|-----|
| 1 | A |
| 1 | B |
| 2 | A |
I need to create one column for each table, and the dummies values if it's present.
| id | city| is_tbl_1 | is_tbl_2 | is_tbl_3 |
|----|-----|-----------|-------------|------------|
| 1 | A | 1 | 0 | 1 |
| 1 | B | 1 | 1 | 1 |
| 2 | A | 0 | 0 | 1 |
| 2 | C | 1 | 0 | 0 |
| 2 | B | 0 | 1 | 0 |
| 3 | C | 0 | 1 | 0 |
I have tried to add the columns is_tbl# myself on three different selects, UNION all the three tables and group, but it looks ugly, is there a better way to do it?
You can outer-join the 3 tables on id and city, then group by the id and city, and finally count the number of non-null values of the city columns :
SELECT
COALESCE (t1.id, t2.id, t3.id) AS id
, COALESCE (t1.city, t2.city, t3.city) AS city
, count(*) FILTER (WHERE t1.city IS NOT NULL) AS is_tbl_1
, count(*) FILTER (WHERE t2.city IS NOT NULL) AS is_tbl_2
, count(*) FILTER (WHERE t3.city IS NOT NULL) AS is_tbl_3
FROM
t1 AS t1
FULL OUTER JOIN
t2 AS t2 ON t1.id = t2.id AND t1.city = t2.city
FULL OUTER JOIN
t3 AS t3 ON t1.id = t3.id AND t1.city = t3.city
GROUP BY
1,2
ORDER BY
1,2
I have a table as such (tbl):
+----+------+-----+
| pk | attr | val |
+----+------+-----+
| 0 | ohif | 4 |
| 1 | foha | 56 |
| 2 | slns | 2 |
| 3 | faso | 11 |
+----+------+-----+
And another table in n-to-1 relationship with tbl (tbl2):
+----+-----+
| pk | rel |
+----+-----+
| 0 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 2 |
| 5 | 3 |
| 6 | 1 |
| 7 | 2 |
+----+-----+
(tbl2.rel -> tbl.pk.)
I would like to select only the rows from tbl which are in relationship with at least n rows from tbl2.
I.e., for n = 2, I want this table:
+----+------+-----+
| pk | attr | val |
+----+------+-----+
| 0 | ohif | 4 |
| 1 | foha | 56 |
| 2 | slns | 2 |
+----+------+-----+
This is the solution I came up with:
SELECT DISTINCT ON (tbl.pk) tbl.*
FROM (
SELECT tbl.pk
FROM tbl
RIGHT OUTER JOIN tbl2 ON tbl2.rel = tbl.pk
GROUP BY tbl.pk
HAVING COUNT(tbl2.*) >= 2 -- n
) AS tbl_candidates
LEFT OUTER JOIN tbl ON tbl_candidates.pk = tbl.pk
Can it be done without selecting the candidates with a subquery and re-joining the table with itself?
I'm on Postgres 10. A standard SQL solution would be better, but a Postgres solution is acceptable.
OK, just join once, as below:
select
t1.pk,
t1.attr,
t1.val
from
tbl t1
join
tbl2 t2 on t1.pk = t2.rel
group by
t1.pk,
t1.attr,
t1.val
having(count(1)>=2) order by t1.pk;
pk | attr | val
----+------+-----
0 | ohif | 4
1 | foha | 56
2 | slns | 2
(3 rows)
Or just join once and use CTE(with clause), as below:
with tmp as (
select rel from tbl2 group by rel having(count(1)>=2)
)
select b.* from tmp t join tbl b on t.rel = b.pk order by b.pk;
pk | attr | val
----+------+-----
0 | ohif | 4
1 | foha | 56
2 | slns | 2
(3 rows)
Is the SQL clearer?
I want to find how many times each player has max score based on created_at.
In below table.
player_id 1 has two times max score on date 12 and 13.
player_id 2 has one time max score on date 14.
So i want to check it for player_id = 1. how many time this player get max score.
+-----------+-------+-------------+------------+
| player_id | score | sector | created_at |
+-----------+-------+-------------+------------+
| 1 | 25 | Midfielder | 2017-12-12 |
| 2 | 23 | Defender | 2017-12-12 |
| 3 | 24 | Goalkeeper | 2017-12-12 |
| 4 | 20 | Midfielder | 2017-12-12 |
| 1 | 26 | Midfielder | 2017-12-13 |
| 2 | 20 | Defender | 2017-12-13 |
| 3 | 19 | Goalkeeper | 2017-12-13 |
| 4 | 16 | Midfielder | 2017-12-13 |
| 1 | 18 | Midfielder | 2017-12-14 |
| 2 | 20 | Defender | 2017-12-14 |
| 3 | 12 | Goalkeeper | 2017-12-14 |
+-----------+-------+-------------+------------+
You can use the following code,
SELECT PLAYER_ID, COUNT(*) MAX_SCORE_COUNT
FROM
(
SELECT player_id PLAYER_ID FROM YOUR_TABLE_NAME a
WHERE a.score = ( SELECT MAX(b.score) FROM YOUR_TABLE_NAME b WHERE b.created_at = a.created_at)
) s
GROUP BY PLAYER_ID
This query return number of times each player got max score based on created_at.
If you want to check it for player_id = 1 then you can use,
SELECT PLAYER_ID, COUNT(*) MAX_SCORE_COUNT
FROM
(
SELECT player_id PLAYER_ID FROM YOUR_TABLE_NAME a
WHERE a.score = ( SELECT MAX(b.score) FROM YOUR_TABLE_NAME b WHERE b.created_at = a.created_at)
) s
WHERE PLAYER_ID = 1
GROUP BY PLAYER_ID
I have a table like this
Event ID | Contract ID | Event date | Amount |
----------------------------------------------
1 | 1 | 2009-01-01 | 100 |
2 | 1 | 2009-01-02 | 20 |
3 | 1 | 2009-01-03 | 50 |
4 | 2 | 2009-01-01 | 80 |
5 | 2 | 2009-01-04 | 30 |
For each contract I need to fetch the latest event and amount associated with the event and get something like this
Event ID | Contract ID | Event date | Amount |
----------------------------------------------
3 | 1 | 2009-01-03 | 50 |
5 | 2 | 2009-01-04 | 30 |
I can't figure out how to group the data correctly. Any ideas?
Thanks in advance.
SQL 2k5/2k8:
with cte_ranked as (
select *
, row_number() over (
partition by ContractId order by EvantDate desc) as [rank]
from [table])
select *
from cte_ranked
where [rank] = 1;
SQL 2k:
select t.*
from table as t
join (
select max(EventDate) as MaxDate
, ContractId
from table
group by ContractId) as mt
on t.ContractId = mt.ContractId
and t.EventDate = mt.MaxDate