Input file
SN ID
------------
1 55
2 -25
3 62
4 -0.05
5 0.0
Output file should be after sorting
SN ID
-------
3 62
1 55
5 0.0
4 -0.05
2 -25
Using this SQL Server command need to modify by logic
select top 4 *
from filename
order by ID desc
It sounds as though perhaps your ID column is actually some sort of text, rather than numeric, type. If so, then casting the column to a decimal and then sorting should fix the problem:
SELECT TOP 4 *
FROM filename
ORDER BY CAST(ID AS DECIMAL(10,4)) DESC;
Note that if the above query does work, then you should seriously consider not storing numeric information as text.
You are missing a WHERE clause. If you need to filter only by negative values just add the following:
select top 4 *
from filename
where ID < 0
order by ID desc
I want to replace values in a column with randomized values
NO LINE
-- ----
1 1
1 2
1 3
1 4
2 1
2 2
3 1
4 1
4 2
I want to randomize column NO and replace with random values. I have 5 million records and doing something like below script gives me 5 million unique NO's but as you can see NO is not unique and i want the same random value assigned for the same NO.
UPDATE table1
SET NO= abs(checksum(NewId())) % 100000000
I want my resultant dataset like below
NO LINE
------ ----
99 1
99 2
99 3
99 4
1092 1
1092 2
3456 1
41098 1
41098 2
I would recommend rand() with a seed:
UPDATE table1
SET NO = FLOOR(rand(NO) * 100000000);
This runs a slight risk of collisions, so two different NO rows could get the same value.
If the numbers do not need to be "random" you can give them consecutive values in an arbitrary order and avoid collisions:
with toupdate as (
select t1.*,
dense_rank() over (order by rand(NO), no) as new_no
from t
)
update toupdate
set no = new_no;
My table contains data about Employee. However it is a temporary table and EmployeeID here isn't the primary key. The table may contain a given EmployeeID multiple times.
Now, I have to select batch of records of batchSize, let's consider 200 for now. I'll send these batches to multiple threads.
I have written this query:
WITH SingleBatch AS
(
SELECT
*,
ROW_NUMBER() OVER(ORDER BY EmployeeId) AS RowNumber
FROM
TemperoryTable
)
SELECT *
FROM SingleBatch
WHERE RowNumber BETWEEN 1 AND 200;
the result might be:
EmployeeID EffectiveDate
1 123 01/01/2016
2 541 01/01/2016
------------------------
------------------------
200 978 18/06/2015
for one batch.
This works fine and row numbers change with thread number.
Now suppose, second batch starts with EmployeeId 978. Then this employee will be in first batch as well as second batch. That is, same employee is being sent to multiple threads and may possibly cause conflict.
Although the scenario is very rare, I must avoid this.
What could be the possible solution here?
Sorry I don't get it before, you wish same empolyee can be gotten together? but the total return rows count possible is not fix number. May this is helpful for you.
;WITH t(RowNumber,EmployeeId,other)AS
(
SELECT 1,'a','1' UNION ALL
SELECT 2,'a','12' UNION ALL
SELECT 3,'a','13' UNION ALL
SELECT 4,'b','21' UNION ALL
SELECT 5,'d','41' UNION ALL
SELECT 6,'c','31' UNION ALL
SELECT 7,'c','32'
)
SELECT *,DENSE_RANK()OVER(ORDER BY EmployeeId) AS FilterID,RANK()OVER(ORDER BY EmployeeId) RowsCount FROM t
RowNumber EmployeeId other FilterID RowsCount
----------- ---------- ----- -------------------- --------------------
2 a 12 1 1
3 a 13 1 1
1 a 1 1 1
4 b 21 2 4
6 c 31 3 5
7 c 32 3 5
5 d 41 4 7
Same employeeid has same FilterID, and the RowsCount to control return rows count.
You should get data by RowsCount but rownumber.
For example:
Actual return 6 lines when the RowsCount between 1 and 5.
because the employeeID c have two lines.
Between mean RowNumber>=1 and RowNumber<=200
So next batch should be
RowNumber BETWEEN 201 AND 400
also you can change where clause to
RowNumber>=1 and RowNumber <200 (1-199)
RowNumber>=200 and RowNumber <400 (200-399)
I have a table called crewWork as follows :
CREATE TABLE crewWork(
FloorNumber int, AptNumber int, WorkType int, simTime int )
After the table was populated, I need to know how many times a change in apt occurred and how many times a change in floor occurred. Usually I expect to find 10 rows on each apt and 40-50 on each floor.
I could just write a scalar function for that, but I was wondering if there's any way to do that in t-SQL without having to write scalar functions.
Thanks
The data will look like this:
FloorNumber AptNumber WorkType simTime
1 1 12 10
1 1 12 25
1 1 13 35
1 1 13 47
1 2 12 52
1 2 12 59
1 2 13 68
1 1 14 75
1 4 12 79
1 4 12 89
1 4 13 92
1 4 14 105
1 3 12 115
1 3 13 129
1 3 14 138
2 1 12 142
2 1 12 150
2 1 14 168
2 1 14 171
2 3 12 180
2 3 13 190
2 3 13 200
2 3 14 205
3 3 14 216
3 4 12 228
3 4 12 231
3 4 14 249
3 4 13 260
3 1 12 280
3 1 13 295
2 1 14 315
2 2 12 328
2 2 14 346
I need the information for a report, I don't need to store it anywhere.
If you use the accepted answer as written now (1/6/2023), you get correct results with the OP dataset, but I think you can get wrong results with other data.
CONFIRMED: ACCEPTED ANSWER HAS A MISTAKE (as of 1/6/2023)
I explain the potential for wrong results in my comments on the accepted answer.
In this db<>fiddle, I demonstrate the wrong results. I use a slightly modified form of accepted answer (my syntax works in SQL Server and PostgreSQL). I use a slightly modified form of the OP's data (I change two rows). I demonstrate how the accepted answer can be changed slightly, to produce correct results.
The accepted answer is clever but needs a small change to produce correct results (as demonstrated in the above db<>fiddle and described here:
Instead of doing this as seen in the accepted answer COUNT(DISTINCT AptGroup)...
You should do thisCOUNT(DISTINCT CONCAT(AptGroup, '_', AptNumber))...
DDL:
SELECT * INTO crewWork FROM (VALUES
-- data from question, with a couple changes to demonstrate problems with the accepted answer
-- https://stackoverflow.com/q/8666295/1175496
--FloorNumber AptNumber WorkType simTime
(1, 1, 12, 10 ),
-- (1, 1, 12, 25 ), -- original
(2, 1, 12, 25 ), -- new, changing FloorNumber 1->2->1
(1, 1, 13, 35 ),
(1, 1, 13, 47 ),
(1, 2, 12, 52 ),
(1, 2, 12, 59 ),
(1, 2, 13, 68 ),
(1, 1, 14, 75 ),
(1, 4, 12, 79 ),
-- (1, 4, 12, 89 ), -- original
(1, 1, 12, 89 ), -- new , changing AptNumber 4->1->4 ges)
(1, 4, 13, 92 ),
(1, 4, 14, 105 ),
(1, 3, 12, 115 ),
...
DML:
;
WITH groupedWithConcats as (SELECT
*,
CONCAT(AptGroup,'_', AptNumber) as AptCombo,
CONCAT(FloorGroup,'_',FloorNumber) as FloorCombo
-- SQL SERVER doesnt have TEMPORARY keyword; Postgres doesn't understand # for temp tables
-- INTO TEMPORARY groupedWithConcats
FROM
(
SELECT
-- the columns shown in Andriy's answer:
-- https://stackoverflow.com/a/8667477/1175496
ROW_NUMBER() OVER ( ORDER BY simTime) as RN,
-- AptNumber
AptNumber,
ROW_NUMBER() OVER (PARTITION BY AptNumber ORDER BY simTime) as RN_Apt,
ROW_NUMBER() OVER ( ORDER BY simTime)
- ROW_NUMBER() OVER (PARTITION BY AptNumber ORDER BY simTime) as AptGroup,
-- FloorNumber
FloorNumber,
ROW_NUMBER() OVER (PARTITION BY FloorNumber ORDER BY simTime) as RN_Floor,
ROW_NUMBER() OVER ( ORDER BY simTime)
- ROW_NUMBER() OVER (PARTITION BY FloorNumber ORDER BY simTime) as FloorGroup
FROM crewWork
) grouped
)
-- if you want to see how the groupings work:
-- SELECT * FROM groupedWithConcats
-- otherwise just run this query to see the counts of "changes":
SELECT
COUNT(DISTINCT AptCombo)-1 as CountAptChangesWithConcat_Correct,
COUNT(DISTINCT AptGroup)-1 as CountAptChangesWithoutConcat_Wrong,
COUNT(DISTINCT FloorCombo)-1 as CountFloorChangesWithConcat_Correct,
COUNT(DISTINCT FloorGroup)-1 as CountFloorChangesWithoutConcat_Wrong
FROM groupedWithConcats;
ALTERNATIVE ANSWER
The accepted-answer may eventually get updated to remove the mistake. If that happens I can remove my warning but I still want leave you with this alternative way to produce the answer.
My approach goes like this: "check the previous row, if the value is different in previous row vs current row, then there is a change". SQL doesn't have idea or row order functions per se (at least not like in Excel for example; )
Instead, SQL has window functions. With SQL's window functions, you can use the window function RANK plus a self-JOIN technique as seen here to combine current row values and previous row values so you can compare them. Here is a db<>fiddle showing my approach, which I pasted below.
The intermediate table, showing the columns which has a value 1 if there is a change, 0 otherwise (i.e. FloorChange, AptChange), is shown at the bottom of the post...
DDL:
...same as above...
DML:
;
WITH rowNumbered AS (
SELECT
*,
ROW_NUMBER() OVER ( ORDER BY simTime) as RN
FROM crewWork
)
,joinedOnItself AS (
SELECT
rowNumbered.*,
rowNumberedRowShift.FloorNumber as FloorShift,
rowNumberedRowShift.AptNumber as AptShift,
CASE WHEN rowNumbered.FloorNumber <> rowNumberedRowShift.FloorNumber THEN 1 ELSE 0 END as FloorChange,
CASE WHEN rowNumbered.AptNumber <> rowNumberedRowShift.AptNumber THEN 1 ELSE 0 END as AptChange
FROM rowNumbered
LEFT OUTER JOIN rowNumbered as rowNumberedRowShift
ON rowNumbered.RN = (rowNumberedRowShift.RN+1)
)
-- if you want to see:
-- SELECT * FROM joinedOnItself;
SELECT
SUM(FloorChange) as FloorChanges,
SUM(AptChange) as AptChanges
FROM joinedOnItself;
Below see the first few rows of the intermediate table (joinedOnItself). This shows how my approach works. Note the last two columns, which have a value of 1 when there is a change in FloorNumber compared to FloorShift (noted in FloorChange), or a change in AptNumber compared to AptShift (noted in AptChange).
floornumber
aptnumber
worktype
simtime
rn
floorshift
aptshift
floorchange
aptchange
1
1
12
10
1
0
0
2
1
12
25
2
1
1
1
0
1
1
13
35
3
2
1
1
0
1
1
13
47
4
1
1
0
0
1
2
12
52
5
1
1
0
1
1
2
12
59
6
1
2
0
0
1
2
13
68
7
1
2
0
0
Note instead of using the window function RANK and JOIN, you could use the window function LAG to compare values in the current row to the previous row directly (no need to JOIN). I don't have that solution here, but it is described in the Wikipedia article example:
Window functions allow access to data in the records right before and after the current record.
If I am not missing anything, you could use the following method to find the number of changes:
determine groups of sequential rows with identical values;
count those groups;
subtract 1.
Apply the method individually for AptNumber and for FloorNumber.
The groups could be determined like in this answer, only there's isn't a Seq column in your case. Instead, another ROW_NUMBER() expression could be used. Here's an approximate solution:
;
WITH marked AS (
SELECT
FloorGroup = ROW_NUMBER() OVER ( ORDER BY simTime)
- ROW_NUMBER() OVER (PARTITION BY FloorNumber ORDER BY simTime),
AptGroup = ROW_NUMBER() OVER ( ORDER BY simTime)
- ROW_NUMBER() OVER (PARTITION BY AptNumber ORDER BY simTime)
FROM crewWork
)
SELECT
FloorChanges = COUNT(DISTINCT FloorGroup) - 1,
AptChanges = COUNT(DISTINCT AptGroup) - 1
FROM marked
(I'm assuming here that the simTime column defines the timeline of changes.)
UPDATE
Below is a table that shows how the distinct groups are obtained for AptNumber.
AptNumber RN RN_Apt AptGroup (= RN - RN_Apt)
--------- -- ------ ---------
1 1 1 0
1 2 2 0
1 3 3 0
1 4 4 0
2 5 1 4
2 6 2 4
2 7 3 4
1 8 5 => 3
4 9 1 8
4 10 2 8
4 11 3 8
4 12 4 8
3 13 1 12
3 14 2 12
3 15 3 12
1 16 6 10
… … … …
Here RN is a pseudo-column that stands for ROW_NUMBER() OVER (ORDER BY simTime). You can see that this is just a sequence of rankings starting from 1.
Another pseudo-column, RN_Apt contains values produces by the other ROW_NUMBER, namely ROW_NUMBER() OVER (PARTITION BY AptNumber ORDER BY simTime). It contains rankings within individual groups of identical AptNumber values. You can see that, for a newly encountered value, the sequence starts over, and for a recurring one, it continues where it stopped last time.
You can also see from the table that if we subtract RN from RN_Apt (could be the other way round, doesn't matter in this situation), we get the value that uniquely identifies every distinct group of same AptNumber values. You might as well call that value a group ID.
So, now that we've got these IDs, it only remains for us to count them (count distinct values, of course). That will be the number of groups, and the number of changes is one less (assuming the first group is not counted as a change).
add an extra column changecount
CREATE TABLE crewWork(
FloorNumber int, AptNumber int, WorkType int, simTime int ,changecount int)
increment changecount value for each updation
if want to know count for each field then add columns corresponding to it for changecount
Assuming that each record represents a different change, you can find changes per floor by:
select FloorNumber, count(*)
from crewWork
group by FloorNumber
And changes per apartment (assuming AptNumber uniquely identifies apartment) by:
select AptNumber, count(*)
from crewWork
group by AptNumber
Or (assuming AptNumber and FloorNumber together uniquely identifies apartment) by:
select FloorNumber, AptNumber, count(*)
from crewWork
group by FloorNumber, AptNumber
Consider the following table:
ID nonUniqueID value total
--------------------------
1 12345 5 x
2 12345 10 x
3 789 20 x
4 789 5 x
I need to make a query something like this (psuedo SQL), which will work within Access 2007:
UPDATE table
SET total = SUM(value)
WHERE nonUniqueID IS SAME;
The result should be as follows:
ID nonUniqueID value total
--------------------------
1 12345 5 15
2 12345 10 15
3 789 20 25
4 789 5 25
I've tried group bys, but I got odd results that quite frankly, I could not interpret. Does anybody know how I could achieve something like this?
Not sure if this works in Access or not, but give it a try:
update table t1
inner join (
select nonUniqueID, sum(value) as SumValue
from table
group by nonUniqueID
) t2 on t1.nonUniqueID = t2.nonUniqueID
set t1.total = t2.SumValue
Update: Based on this question, it looks like it is not going to work. But give it a shot! If it doesn't, you can use the approach suggested in that question.
Another possible option:
update t
set total = (select SUM(value) from table where nonUniqueID = t.nonUniqueID)
from table t