I am new in SQL lite, I have a datetime column in this format:
id
datetime
1
2020-12-26 19:08:49
2
2020-12-26 19:08:50
3
2020-12-26 19:08:51
4
2020-12-26 19:08:51
5
2020-12-26 19:09:07
6
2020-12-26 19:11:45
7
2020-12-26 19:52:49
8
2020-12-26 19:52:50
How can i compute the difference between the first element with the 2nd
the 3rd with 4th element ??
Use window function FIRST_VALUE() to get the datetime of the the 1st row and with the function strftime() you can calculate the difference of each row:
SELECT *
FROM (
SELECT id,
strftime('%s', datetime) - strftime('%s', FIRST_VALUE(datetime) OVER (ORDER BY id)) AS diff_in_secs
FROM tablename
)
WHERE id > 1
Or with a self join:
SELECT t.id,
strftime('%s', t.datetime) - strftime('%s', m.datetime)
FROM tablename t
INNER JOIN (SELECT * FROM tablename ORDER BY id LIMIT 1) m
ON m.id < t.id
I used id and datetime for the column names and tablename for the table's name, you can change them to the actual ones.
See the demo.
Results:
> id | diff_in_secs
> -: | -----------:
> 2 | 1
> 3 | 2
> 4 | 2
> 5 | 18
> 6 | 176
> 7 | 2640
> 8 | 2641
Related
how do i do a select where count = select all sequence rows has the same column value as current column value only if there 3 in sequence (row after row with no holes)
NAME | NUM | DATE
---------------------------------
Name 1 | 1 | '2019-01-07 12:11:11:001'
Name 2 | 1 | '2019-01-07 12:11:12:002'
Name 3 | 3 | '2019-01-07 12:11:13:003'
Name 4 | 2 | '2019-01-07 12:11:14:004'
Name 5 | 2 | '2019-01-07 12:11:15:005'
Name 6 | 2 | '2019-01-07 12:11:16:006'
Name 7 | 4 | '2019-01-07 12:11:17:007'
Name 8 | 5 | '2019-01-07 12:11:18:008'
The results should be where count sequence=3
NAME | NUM | DATE
---------------------------------
Name 4 | 2 | '2019-01-07 12:11:14:004'
Name 5 | 2 | '2019-01-07 12:11:15:005'
Name 6 | 2 | '2019-01-07 12:11:16:006'
because 2 appears 3 times in sequence
You can use the following query:
SELECT [NAME], [NUM], [DATE],
ROW_NUMBER() OVER (ORDER BY [DATE]) -
ROW_NUMBER() OVER (PARTITION BY NUM ORDER BY [DATE]) AS grp
FROM mytable
to get:
NAME NUM DATE grp
----------------------------------------
Name 1 1 2019-01-07 12:11:11 0
Name 2 1 2019-01-07 12:11:12 0
Name 4 2 2019-01-07 12:11:13 3
Name 5 2 2019-01-07 12:11:14 3
Name 6 2 2019-01-07 12:11:15 3
Name 3 3 2019-01-07 12:11:16 2
Name 7 4 2019-01-07 12:11:17 6
Name 8 5 2019-01-07 12:11:18 7
As you can see calculated column grp can be used in order to identify islands of consecutive records having the same NUM value.
You can then wrap the above query in a CTE and do:
;WITH GroupCTE AS (
SELECT [NAME], [NUM], [DATE],
ROW_NUMBER() OVER (ORDER BY [DATE]) -
ROW_NUMBER() OVER (PARTITION BY NUM ORDER BY [DATE]) AS grp
FROM mytable
)
SELECT t.*
FROM GroupCTE AS t
JOIN (SELECT NUM, grp
FROM GroupCTE
GROUP BY NUM, grp
HAVING COUNT(*) = 3) AS g ON t.NUM = g.NUM AND t.grp = g.grp
I can use a traditional subquery approach to count the occurrences in the last ten minutes. For example, this:
drop table if exists [dbo].[readings]
go
create table [dbo].[readings](
[server] [int] NOT NULL,
[sampled] [datetime] NOT NULL
)
go
insert into readings
values
(1,'20170101 08:00'),
(1,'20170101 08:02'),
(1,'20170101 08:05'),
(1,'20170101 08:30'),
(1,'20170101 08:31'),
(1,'20170101 08:37'),
(1,'20170101 08:40'),
(1,'20170101 08:41'),
(1,'20170101 09:07'),
(1,'20170101 09:08'),
(1,'20170101 09:09'),
(1,'20170101 09:11')
go
-- Count in the last 10 minutes - example periods 08:31 to 08:40, 09:12 to 09:21
select server,sampled,(select count(*) from readings r2 where r2.server=r1.server and r2.sampled <= r1.sampled and r2.sampled > dateadd(minute,-10,r1.sampled)) as countinlast10minutes
from readings r1
order by server,sampled
go
How can I use a window function to obtain the same result ? I've tried this:
select server,sampled,
count(case when sampled <= r1.sampled and sampled > dateadd(minute,-10,r1.sampled) then 1 else null end) over (partition by server order by sampled rows between unbounded preceding and current row) as countinlast10minutes
-- count(case when currentrow.sampled <= r1.sampled and currentrow.sampled > dateadd(minute,-10,r1.sampled) then 1 else null end) over (partition by server order by sampled rows between unbounded preceding and current row) as countinlast10minutes
from readings r1
order by server,sampled
But the result is just the running count. Any system variable that refers to the current row pointer ? currentrow.sampled ?
This isn't a very pleasing answer but one possibility is to first create a helper table with all the minutes
CREATE TABLE #DateTimes(datetime datetime primary key);
WITH E1(N) AS
(
SELECT 1 FROM (VALUES(1),(1),(1),(1),(1),
(1),(1),(1),(1),(1)) V(N)
) -- 1*10^1 or 10 rows
, E2(N) AS (SELECT 1 FROM E1 a, E1 b) -- 1*10^2 or 100 rows
, E4(N) AS (SELECT 1 FROM E2 a, E2 b) -- 1*10^4 or 10,000 rows
, E8(N) AS (SELECT 1 FROM E4 a, E4 b) -- 1*10^8 or 100,000,000 rows
,R(StartRange, EndRange)
AS (SELECT MIN(sampled),
MAX(sampled)
FROM readings)
,N(N)
AS (SELECT ROW_NUMBER()
OVER (
ORDER BY (SELECT NULL)) AS N
FROM E8)
INSERT INTO #DateTimes
SELECT TOP (SELECT 1 + DATEDIFF(MINUTE, StartRange, EndRange) FROM R) DATEADD(MINUTE, N.N - 1, StartRange)
FROM N,
R;
And then with that in place you could use ROWS BETWEEN 9 PRECEDING AND CURRENT ROW
WITH T1 AS
( SELECT Server,
MIN(sampled) AS StartRange,
MAX(sampled) AS EndRange
FROM readings
GROUP BY Server )
SELECT Server,
sampled,
Cnt
FROM T1
CROSS APPLY
( SELECT r.sampled,
COUNT(r.sampled) OVER (ORDER BY N.datetime ROWS BETWEEN 9 PRECEDING AND CURRENT ROW) AS Cnt
FROM #DateTimes N
LEFT JOIN readings r
ON r.sampled = N.datetime
AND r.server = T1.server
WHERE N.datetime BETWEEN StartRange AND EndRange ) CA
WHERE CA.sampled IS NOT NULL
ORDER BY sampled
The above assumes that there is at most one sample per minute and that all the times are exact minutes. If this isn't true it would need another table expression pre-aggregating by datetimes rounded to the minute.
As far as I know, there is not a simple exact replacement for your subquery using window functions.
Window functions operate on a set of rows and allow you to work with them based on partitions and order.
What you are trying to do isn't the type of partitioning that we can work with in window functions.
To generate the partitions we would need to be able to use window functions in this instance would just result in overly complicated code.
I would suggest cross apply() as an alternative to your subquery.
I am not sure if you meant to restrict your results to within 9 minutes, but with sampled > dateadd(...) that is what is happening in your original subquery.
Here is what a window function could look like based on partitioning your samples into 10 minute windows, along with a cross apply() version.
select
r.server
, r.sampled
, CrossApply = x.CountRecent
, OriginalSubquery = (
select count(*)
from readings s
where s.server=r.server
and s.sampled <= r.sampled
/* doesn't include 10 minutes ago */
and s.sampled > dateadd(minute,-10,r.sampled)
)
, Slices = count(*) over(
/* partition by server, 10 minute slices, not the same thing*/
partition by server, dateadd(minute,datediff(minute,0,sampled)/10*10,0)
order by sampled
)
from readings r
cross apply (
select CountRecent=count(*)
from readings i
where i.server=r.server
/* changed to >= */
and i.sampled >= dateadd(minute,-10,r.sampled)
and i.sampled <= r.sampled
) as x
order by server,sampled
results: http://rextester.com/BMMF46402
+--------+---------------------+------------+------------------+--------+
| server | sampled | CrossApply | OriginalSubquery | Slices |
+--------+---------------------+------------+------------------+--------+
| 1 | 01.01.2017 08:00:00 | 1 | 1 | 1 |
| 1 | 01.01.2017 08:02:00 | 2 | 2 | 2 |
| 1 | 01.01.2017 08:05:00 | 3 | 3 | 3 |
| 1 | 01.01.2017 08:30:00 | 1 | 1 | 1 |
| 1 | 01.01.2017 08:31:00 | 2 | 2 | 2 |
| 1 | 01.01.2017 08:37:00 | 3 | 3 | 3 |
| 1 | 01.01.2017 08:40:00 | 4 | 3 | 1 |
| 1 | 01.01.2017 08:41:00 | 4 | 3 | 2 |
| 1 | 01.01.2017 09:07:00 | 1 | 1 | 1 |
| 1 | 01.01.2017 09:08:00 | 2 | 2 | 2 |
| 1 | 01.01.2017 09:09:00 | 3 | 3 | 3 |
| 1 | 01.01.2017 09:11:00 | 4 | 4 | 1 |
+--------+---------------------+------------+------------------+--------+
Thanks, Martin and SqlZim, for your answers. I'm going to raise a Connect enhancement request for something like %%currentrow that can be used in window aggregates. I'm thinking this would lead to much more simple and natural sql:
select count(case when sampled <= %%currentrow.sampled and sampled > dateadd(minute,-10,%%currentrow.sampled) then 1 else null end) over (...whatever the window is...)
We can already use expressions like this:
select count(case when sampled <= getdate() and sampled > dateadd(minute,-10,getdate()) then 1 else null end) over (...whatever the window is...)
so thinking would be great if we could reference a column that's in the current row.
I have a table containing employees id, year id, client id, and the number of sales. For example:
--------------------------------------
id_emp | id_year | sales | client id
--------------------------------------
4 | 1 | 14 | 1
4 | 1 | 10 | 2
4 | 2 | 11 | 1
4 | 2 | 17 | 2
For a employee, I want to obtain rows with the minimum sales per year and the minimum sales of the previous year.
One of the queries I tried is the following:
select distinct
id_emp,
id_year,
MIN(sales) OVER(partition by id_emp, id_year) AS min_sales,
LAG(min(sales), 1) OVER(PARTITION BY id_emp, id_year
ORDER BY id_emp, id_year) AS previous
from facts
where id_emp = 4
group by id_emp, id_year, sales;
I get the result:
-------------------------------------
id_emp | id_year | sales | previous
-------------------------------------
4 | 1 | 10 | (null)
4 | 1 | 10 | 10
4 | 2 | 11 | (null)
but I expect to get:
-------------------------------------
id_emp | id_year | sales | previous
-------------------------------------
4 | 1 | 10 | (null)
4 | 2 | 11 | 10
SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE EMPLOYEE_SALES ( id_emp, id_year, sales, client_id ) AS
SELECT 4, 1, 14, 1 FROM DUAL
UNION ALL SELECT 4, 1, 10, 2 FROM DUAL
UNION ALL SELECT 4, 2, 11, 1 FROM DUAL
UNION ALL SELECT 4, 2, 17, 2 FROM DUAL;
Query 1:
SELECT ID_EMP,
ID_YEAR,
SALES AS SALES,
LAG( SALES ) OVER ( PARTITION BY ID_EMP ORDER BY ID_YEAR ) AS PREVIOUS
FROM (
SELECT e.*,
ROW_NUMBER() OVER ( PARTITION BY id_emp, id_year ORDER BY sales ) AS RN
FROM EMPLOYEE_SALES e
)
WHERE rn = 1
Query 2:
SELECT ID_EMP,
ID_YEAR,
MIN( SALES ) AS SALES,
LAG( MIN( SALES ) ) OVER ( PARTITION BY ID_EMP ORDER BY ID_YEAR ) AS PREVIOUS
FROM EMPLOYEE_SALES
GROUP BY ID_EMP, ID_YEAR
Results - Both give the same output:
| ID_EMP | ID_YEAR | SALES | PREVIOUS |
|--------|---------|-------|----------|
| 4 | 1 | 10 | (null) |
| 4 | 2 | 11 | 10 |
You mean like this?
select id_emp, id_year, min(sales) as min_sales,
lag(min(sales)) over (partition by id_emp order by id_year) as prev_year_min_sales
from facts
where id_emp = 4
group by id_emp, id_year;
I believe it is because you are using sales column in your group by statement.
Try to remove it and just use
GROUP BY id_emp,id_year
You could get your desired output using ROW_NUMBER() and LAG() analytic functions.
For example,
Table
SQL> SELECT * FROM t;
ID_EMP ID_YEAR SALES CLIENT_ID
---------- ---------- ---------- ----------
4 1 14 1
4 1 10 2
4 2 11 1
4 2 17 2
Query
SQL> WITH DATA AS
2 (SELECT t.*,
3 row_number() OVER(PARTITION BY id_emp, id_year ORDER BY sales) rn
4 FROM t
5 )
6 SELECT id_emp,
7 id_year ,
8 sales ,
9 lag(sales) over(order by sales) previous
10 FROM DATA
11 WHERE rn =1;
ID_EMP ID_YEAR SALES PREVIOUS
---------- ---------- ---------- ----------
4 1 10
4 2 11 10
I have the following table in my database:
Month|Year | Value
1 |2013 | 100
4 |2013 | 101
8 |2013 | 102
2 |2014 | 103
4 |2014 | 104
How can I fill in "missing" rows from the data, so that if I query from 2013-03 through 2014-03, I would get:
Month|Year | Value
3 |2013 | 100
4 |2013 | 101
5 |2013 | 101
6 |2013 | 101
7 |2013 | 101
8 |2013 | 102
9 |2013 | 102
10 |2013 | 102
11 |2013 | 102
12 |2013 | 102
1 |2014 | 102
2 |2014 | 103
3 |2014 | 103
As you can see I want to repeat the previous Value for a missing row.
I have created a SQL Fiddle of this solution for you to play with.
Essentially it creates a Work Table #Months and then Cross joins this will all years in your data set. This produces a complete list of all months for all years. I then left join the Test data provided in your example (Table named TEST - see SQL fiddle for schema) back into this list to give me a complete list with Values for the months that have them. The next issue to overcome was using the last months values if this months didn't have any. For that, I used a correlated sub-query i.e. joined tblValues back on itself only where it matched the maximum Rank of a row which has a value. This then gives a complete result set!
If you want to filter by year\month you can add this into a WHERE clause just before the final Order By.
Enjoy!
Test Schema
CREATE TABLE TEST( Month tinyint, Year int, Value int)
INSERT INTO TEST(Month, Year, Value)
VALUES
(1,2013,100),
(4,2013,101),
(8,2013,102),
(2,2014,103),
(4,2014,104)
Query
DECLARE #Months Table(Month tinyint)
Insert into #Months(Month)Values (1),(2),(3),(4),(5),(6),(7),(8),(9),(10),(11),(12);
With tblValues as (
select Rank() Over (ORDER BY y.Year, m.Month) as [Rank],
m.Month,
y.Year,
t.Value
from #Months m
CROSS JOIN ( Select Distinct Year from Test ) y
LEFT JOIN Test t on t.Month = m.Month and t.Year = y.Year
)
Select t.Month, t.Year, COALESCE(t.Value, t1.Value) as Value
from tblValues t
left join tblValues t1 on t1.Rank = (
Select Max(tmax.Rank)
From tblValues tmax
Where tmax.Rank < t.Rank AND tmax.Value is not null)
Order by t.Year, t.Month
Can anyone help me with query, I have table
vendorid, agreementid, sales
12001 1004 700
5291 1004 20576
7596 1004 1908
45 103 345
41 103 9087
what is the goal ?
when agreemtneid >1 then show me data when sales is the highest
vendorid agreementid sales
5291 1004 20576
41 103 9087
Any ideas ?
Thx
Well you could try using a CTE and ROW_NUMBER something like
;WITH Vals AS (
SELECT *, ROW_NUMBER() OVER(PARTITION BY AgreementID ORDER BY Sales DESC) RowID
FROM MyTable
WHERE AgreementID > 1
)
SELECT *
FROM Vals
WHERE RowID = 1
This will avoid you returning multiple records with the same sale.
If that was OK you could try something like
SELECT *
FROM MyTable mt INNER JOIN
(
SELECT AgreementID, MAX(Sales) MaxSales
FROM MyTable
WHERE AgreementID > 1
) MaxVals ON mt.AgreementID = MaxVals.AgreementID AND mt.Sales = MaxVals.MaxSales
SELECT TOP 1 WITH TIES *
FROM MyTable
ORDER BY DENSE_RANK() OVER(PARTITION BY agreementid ORDER BY SIGN (SIGN (agreementid - 2) + 1) * sales DESC)
Explanation
We break table MyTable into partitions by agreementid.
For each partition we construct a ranking or its rows.
If agreementid is greater than 1 ranking will be equal to ORDER BY sales DESC.
Otherwise ranking for every single row in partition will be the same: ORDER BY 0 DESC.
See how it looks like:
SELECT *
, SIGN (SIGN (agreementid - 2) + 1) * sales AS x
, DENSE_RANK() OVER(PARTITION BY agreementid ORDER BY SIGN (SIGN (agreementid - 2) + 1) * sales DESC) AS rnk
FROM MyTable
+----------+-------------+-------+-------+-----+
| vendorid | agreementid | sales | x | rnk |
+----------|-------------|-------+-------+-----+
| 0 | 0 | 3 | 0 | 1 |
| -1 | 0 | 7 | 0 | 1 |
| 0 | 1 | 3 | 0 | 1 |
| -1 | 1 | 7 | 0 | 1 |
| 41 | 103 | 9087 | 9087 | 1 |
| 45 | 103 | 345 | 345 | 2 |
| 5291 | 1004 | 20576 | 20576 | 1 |
| 7596 | 1004 | 1908 | 1908 | 2 |
| 12001 | 1004 | 700 | 700 | 3 |
+----------+-------------+-------+-------+-----+
Then using TOP 1 WITH TIES construction we leave only rows where rnk equals 1.
you can try like this.
SELECT TOP 1 sales FROM MyTable WHERE agreemtneid > 1 ORDER BY sales DESC
I really do not know the business logic behind agreement_id > 1. It looks to me you want the max sales (with ties) by agreement id regardless of vendor_id.
First, lets create a simple sample database.
-- Sample table
create table #sales
(
vendor_id int,
agreement_id int,
sales_amt money
);
-- Sample data
insert into #sales values
(12001, 1004, 700),
(5291, 1004, 20576),
(7596, 1004, 1908),
(45, 103, 345),
(41, 103, 9087);
Second, let's solve this problem using a common table expression to get a result set that has each row paired with the max sales by agreement id.
The select statement just applies the business logic to filter the data to get your answer.
-- CTE = max sales for each agreement id
;
with cte_sales as
(
select
vendor_id,
agreement_id,
sales_amt,
max(sales_amt) OVER(PARTITION BY agreement_id) AS max_sales
from
#sales
)
-- Filter by your business logic
select * from cte_sales where sales_amt = max_sales and agreement_id > 1;
The screen shot below shows the exact result you wanted.