After doing CTE Select Order By and then Update, Update results are not ordered the same (TSQL) - tsql

The code is roughly like this:
WITH cte AS
(
SELECT TOP 4 id, due_date, check
FROM table_a a
INNER JOIN table_b b ON a.linkid = b.linkid
WHERE
b.status = 1
AND due_date > GetDate()
ORDER BY due_date, id
)
UPDATE cte
SET check = 1
OUTPUT
INSERTED.id,
INSERTED.due_date
Note: the actual data has same due_date.
When I ran the SELECT statement only inside the cte, I could get the result, for ex: 1, 2, 3, 4.
But after the UPDATE statement, the updated results are: 4, 1, 2, 3
Why is this (order-change) happening?
How to keep or re-order the results back to 1,2,3,4 in this same 1 query?

In MSDN https://msdn.microsoft.com/pl-pl/library/ms177564(v=sql.110).aspx you can read that
There is no guarantee that the order in which the changes are applied
to the table and the order in which the rows are inserted into the
output table or table variable will correspond.
Thats mean you can't solve your problem with only one query. But you still can use one batch to do what you need. Because your output don't guarantee the order then you have to save it in another table and order it after update. This code will return your output values in order that you assume:
declare #outputTable table( id int, due_date date);
with cte as (
select top 4 id, due_date, check
from table_a a
inner join table_b b on a.linkid = b.linkid
where b.status = 1
and due_date > GetDate()
order by due_date, id
)
update cte
set check = 1
output inserted.id, inserted.due_date
into #outputTable;
select *
from #outputTable
order by due_date, id;

Related

Updating a CTE table fail cause of derived or constant field

I'm using MS-SQL 2012
WITH C1
(
SELECT ID, 0 as Match, Field2, Count(*)
FROM TableX
GROUP BY ID, Fields2
)
UPDATE C1 SET Match = 1
WHERE ID = (SELECT MATCHING_ID FROM AnotherTable WHERE ID = C1.ID)
This TSQL statement gives me the following error:
Update or insert of view or function 'C1' failed because it contains a derived or constant field.
Ideally I would like to create a "fake field" named Match and set its default value to 0. Then with the update I would like to Update ONLY the records that have an existing entry on the "AnotherTable".
Any thoughts what am I doing wrong?
Thanks in advanced.
Try doing a Left Outer Join like
SELECT x.ID, ISNULL(a.Matching_ID, 0) as Match, x.Field2, Count(*)
FROM TableX x
LEFT OUTER JOIN AnotherTable a on x.ID = a.ID
GROUP BY x.ID, ISNULL(a.Matching_ID, 0), x.Fields2
without the need of a C1
If I am understanding correctly, the problem is that you are trying to update the CTE table. If you update the table directly you should be fine.
Does this modified version help?
SELECT t.ID
, CASE WHEN (EXISTS (SELECT MATCHING_ID FROM AnotherTable WHERE ID = t.ID)) THEN 1 ELSE 0 END
,t.Field2
,Count(*)
FROM TableX t
GROUP BY ID, Fields2

Updating with Nested Select Statements

I have a table that holds 3 fields of data: Acct#, YMCode, and EmployeeID. The YMCode is an Int that is formatted 201308, 201307, etc. For each Acct#, I need to select the EmployeedID used for the YMCode 201308 and then update all of the other YMCodes for the Acct# to the EmployeedID used in 201308.
so for each customer account in the table...
Update MyTable
Set EmployeeID = EmployeeID used in YMCode 201308
Having a hard time with it.
Put it in a transaction and look at the results before committing, but I think this is what you want:
UPDATE b
SET EmployeeID = a.EmployeeID
FROM MyTable a
INNER JOIN MyTable b
ON a.[Acct#] = b.[Acct#]
where a.YMCode =
(SELECT MAX(YMCode) from MyTable)
To get max YMCode, just add select statement at the end.

How to match records for two different groups?

I have one main table called Event_log which contains all of the records that I need for this query. Within this table there is one column that I'm calling "Grp". To simplify things, assume that there are only two possible values for this Grp: A and B. So now we have one table, Event_log, with one column "Grp" and one more column called "Actual Date". Lastly I want to add one more Flag column to this table, which works as follows.
First, I order all of the records in descending order by date as demonstrated below. Then, I want to flag each Group "A" row with a 1 or a 0. For all "A" rows, if the previous record (earlier in date) = "B" row then I want to flag 1. Otherwise flag a 0. So this initial table looks like this before setting this flag:
Actual Date Grp Flag
1-29-13 A
12-27-12 B
12-26-12 B
12-23-12 A
12-22-12 A
But after these calculations are done, it should look like this:
Actual Date Grp Flag
1-29-13 A 1
12-27-12 B NULL
12-26-12 B NULL
12-23-12 A 0
12-22-12 A 0
How can I do this? This is simpler to describe than it is to query!
You can use something like:
select el.ActualDate
, el.Grp
, Flag = case
when el.grp = 'B' then null
when prev.grp = 'B' then 1
else 0
end
from Event_log el
outer apply
(
select top 1 prev.grp
from Event_log prev
where el.ActualDate > prev.ActualDate
order by prev.ActualDate desc
) prev
order by el.ActualDate desc
SQL Fiddle with demo.
Try this
;with cte as
(
SELECT CAST('01-29-13' As DateTime) ActualDate,'A' Grp
UNION ALL SELECT '12-27-12','B'
UNION ALL SELECT '12-26-12','B'
UNION ALL SELECT '12-23-12','A'
UNION ALL SELECT '12-22-12','A'
)
, CTE2 as
(
SELECT *, ROW_NUMBER() OVER (order by actualdate desc) rn
FROM cte
)
SELECT a.*,
case
when A.Grp = 'A' THEN
CASE WHEN b.Grp = 'B' THEN 1 ELSE 0 END
ELSE NULL
END Flag
from cte2 a
LEFT OUTER JOIN CTE2 b on a.rn + 1 = b.rn

T-SQL how to count the number of duplicate rows then print the outcome?

I have a table ProductNumberDuplicates_backups, which has two columns named ProductID and ProductNumber. There are some duplicate ProductNumbers. How can I count the distinct number of products, then print out the outcome like "() products was backup." ? Because this is inside a stored procedure, I have to use a variable #numrecord as the distinct number of rows. I put my codes like this:
set #numrecord= select distinct ProductNumber
from ProductNumberDuplicates_backups where COUNT(*) > 1
group by ProductID
having Count(ProductNumber)>1
Print cast(#numrecord as varchar)+' product(s) were backed up.'
obviously the error was after the = sign as the select can not follow it. I've search for similar cases but they are just select statements. Please help. Many thanks!
Try
select #numrecord= count(distinct ProductNumber)
from ProductNumberDuplicates_backups
Print cast(#numrecord as varchar)+' product(s) were backed up.'
begin tran
create table ProductNumberDuplicates_backups (
ProductNumber int
)
insert ProductNumberDuplicates_backups(ProductNumber)
select 1
union all
select 2
union all
select 1
union all
select 3
union all
select 2
select * from ProductNumberDuplicates_backups
declare #numRecord int
select #numRecord = count(ProductNumber) from
(select ProductNumber, ROW_NUMBER()
over (partition by ProductNumber order by ProductNumber) RowNumber
from ProductNumberDuplicates_backups) p
where p.RowNumber > 1
print cast(#numRecord as varchar) + ' product(s) were backed up.'
rollback

Query to get row from one table, else random row from another

tblUserProfile - I have a table which holds all the Profile Info (too many fields)
tblMonthlyProfiles - Another table which has just the ProfileID in it (the idea is that this table holds 2 profileids which sometimes become monthly profiles (on selection))
Now when I need to show monthly profiles, I simply do a select from this tblMonthlyProfiles and Join with tblUserProfile to get all valid info.
If there are no rows in tblMonthlyProfile, then monthly profile section is not displayed.
Now the requirement is to ALWAYS show Monthly Profiles. If there are no rows in monthlyProfiles, it should pick up 2 random profiles from tblUserProfile. If there is only one row in monthlyProfiles, it should pick up only one random row from tblUserProfile.
What is the best way to do all this in one single query ?
I thought something like this
select top 2 * from tblUserProfile P
LEFT OUTER JOIN tblMonthlyProfiles M
on M.profileid = P.profileid
ORder by NEWID()
But this always gives me 2 random rows from tblProfile. How can I solve this ?
Try something like this:
SELECT TOP 2 Field1, Field2, Field3, FinalOrder FROM
(
select top 2 Field1, Field2, Field3, FinalOrder, '1' As FinalOrder from tblUserProfile P JOIN tblMonthlyProfiles M on M.profileid = P.profileid
UNION
select top 2 Field1, Field2, Field3, FinalOrder, '2' AS FinalOrder from tblUserProfile P LEFT OUTER JOIN tblMonthlyProfiles M on M.profileid = P.profileid ORDER BY NEWID()
)
ORDER BY FinalOrder
The idea being to pick two monthly profiles (if that many exist) and then 2 random profiles (as you correctly did) and then UNION them. You'll have between 2 and 4 records at that point. Grab the top two. FinalOrder column is an easy way to make sure that you try and get the monthly's first.
If you have control of the table structure, you might save yourself some trouble by simply adding a boolean field IsMonthlyProfile to the UserProfile table. Then it's a single table query, order by IsBoolean, NewID()
In SQL 2000+ compliant syntax you could do something like:
Select ...
From (
Select TOP 2 ...
From tblUserProfile As UP
Where Not Exists( Select 1 From tblMonthlyProfile As MP1 )
Order By NewId()
) As RandomProfile
Union All
Select MP....
From tblUserProfile As UP
Join tblMonthlyProfile As MP
On MP.ProfileId = UP.ProfileId
Where ( Select Count(*) From tblMonthlyProfile As MP1 ) >= 1
Union All
Select ...
From (
Select TOP 1 ...
From tblUserProfile As UP
Where ( Select Count(*) From tblMonthlyProfile As MP1 ) = 1
Order By NewId()
) As RandomProfile
Using SQL 2005+ CTE you can do:
With
TwoRandomProfiles As
(
Select TOP 2 ..., ROW_NUMBER() OVER ( ORDER BY UP.ProfileID ) As Num
From tblUserProfile As UP
Order By NewId()
)
Select MP.Col1, ...
From tblUserProfile As UP
Join tblMonthlyProfile As MP
On MP.ProfileId = UP.ProfileId
Where ( Select Count(*) From tblMonthlyProfile As MP1 ) >= 1
Union All
Select ...
From TwoRandomProfiles
Where Not Exists( Select 1 From tblMonthlyProfile As MP1 )
Union All
Select ...
From TwoRandomProfiles
Where ( Select Count(*) From tblMonthlyProfile As MP1 ) = 1
And Num = 1
The CTE has the advantage of only querying for the random profiles once and the use of the ROW_NUMBER() column.
Obviously, in all the UNION statements the number and type of the columns must match.