Force recalculation of GetDate() for each row - sql-server

When running this command in SQL Server Management Studio
UPDATE LogChange
SET Created = GETDATE()
WHERE id > 6000
something strange happens.. :)
All rows get the same value in the Created column.
How do I "force" SQL Server to recalculate the GetDate for every row?

A cursor solved it
declare #id int;
Declare toLoop cursor for
select Id from LogChange where id > 6000
OPEN toLoop
FETCH NEXT FROM toLoop INTO #id
WHILE ##FETCH_STATUS = 0
BEGIN
Update LogChange set Created = GETDATE() where id = #id
FETCH NEXT FROM toLoop INTO #id
END
close toLoop
DEALLOCATE toLoop

I have found the following “getdate()” pattern extremely useful over the years. Especially when updating multiple tables in the same transaction. Having the time values exactly match had more benefit to me then being accurate to the millisecond on individual rows.
declare #dtNow datetime
SET #dtNow = GETDATE()
UPDATE LogChange
SET Created = #dtNow
WHERE id > 6000

I don't think there is a way to do them in a single query because the operations in the same clause of a query are evaluated all-at-once.

If you want to guarantee that separate values are applied to each row, write a query that definitely does that:
declare #dt datetime
set #dt = GETDATE()
;With Diffs as (
select
*,
ROW_NUMBER() OVER (ORDER BY id) * 10 as Offset
from
LogChange
WHERE id > 6000
)
UPDATE Diffs
SET Created = DATEADD(millisecond,Offset,#dt)
We know that the above will generate separate offsets for each row, and that we're definitely adding those offsets to a fixed value. It has often been observed that GETDATE() will return the same value for all rows but I cannot find any specific documentation that guarantees this, which is why I've also introduced a #dt variable so that I know it's only assigned once.

You can create a scalar function like this one:
CREATE FUNCTION dbo.sf_GetDate(#num int)
RETURNS DateTime
AS
BEGIN
RETURN GETDATE()
END
GO
Then use it like this:
UPDATE LogChange
SET Created = dbo.GetDate(Id)
WHERE id > 6000

Related

Replace Getdate() with stored procedure

We have a job with couple of steps and almost all of the steps use getdate(), but instead we want to get the date from a specific table and column. The table includes only two columns status as ready (doesn't change) and statusdate (dynamic). The plan is to create a stored procedure and replace the getdate() with that stored procedure.
How do I write the stored procedure? How do I declare a variable?
CREATE PROCEDURE SP_DATE
#StatusDate DATETIME
AS
BEGIN
SELECT StatusDate
FROM [DB_Name].[dbo].[Table_Name]
WHERE status = ready
END
Thank you!
Your jobs use getdate() function therefore in order to replace it with custom programmatic object you should use function as well and not a stored procedure. With a function like this
CREATE FUNCTION dbo.StatusDate ()
RETURNS DATETIME
AS
BEGIN
RETURN (SELECT
StatusDate
FROM Table_Name
WHERE status = 'ready')
END
you can replace getdate directly
SELECT
id
FROM Your_Job_List yjl
WHERE yjl.aDate < dbo.StatusDate()--getdate()
yet there are some questions to the design. One biggest single task of RDBMS is joining tables and perhaps a query similar to next one might be better
SELECT
id
FROM Your_Job_List yjl
,Table_Name tn
WHERE yjl.aDate < tn.StatusDate
AND tn.status = 'ready'
CREATE PROCEDURE spRunNextDate
AS
BEGIN
--SET NOCOUNT ON
declare #runDate datetime
select #runDate = MIN(StatusDate)
from [DB_Name].[dbo].[Table_Name]
where [status] = 'ready'
IF (#runDate IS NULL)
BEGIN
PRINT 'NO Dates in Ready State.'
RETURN 0
END
PRINT 'Will Run Date of ' + CAST(#runDate as varchar(20))
-- Notice the MIN or MAX usage above to get only one date per "run"
END
GO
There are huge holes and questions raised in my presumptuous sp above, but it might get you to thinking about why your question implies that there is no parameter. You are going to need a way to mark the day "done" or else it will be run over and over.

Concatenating Time and DateTime in where clause

I am trying to combine a SmallDateTime field and a Time value (result of a scalar-valued function) into a DateTime and I keep getting the following error:
Conversion failed when converting date and/or time from character
string.
Here are the variables used throughout:
DECLARE #STARTDATETIME AS DATETIME
DECLARE #ENDDATETIME AS DATETIME
SELECT #STARTDATETIME = '8/29/2016 12:00:00'
SELECT #ENDDATETIME = '8/30/2016 12:00:00'
Column definitions:
FT_START_DATE SmallDateTime
FT_END_DATE SmallDateTime
FT_START_TIME Int
FT_END_TIME Int
The date fields do not contain timestamps. The time fields are basically 24 hour time without the colon dividers. (Example: 142350 = 14:23:50)
Here's the function that is called in my queries:
USE [PWIN171]
GO
/****** Object: UserDefinedFunction [dbo].[dbo.IPC_Convert_Time] Script Date: 9/13/2016 4:50:49 PM ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER FUNCTION [dbo].[dbo.IPC_Convert_Time]
(
#time int
)
RETURNS time
AS
BEGIN
DECLARE #Result time
SELECT #Result = CONVERT(time
, STUFF(
STUFF(
RIGHT('000000' + CONVERT(varchar(6), #time), 6)
, 5, 0, ':')
, 3, 0, ':')
)
RETURN #Result
END
Example 1 - Fails:
This is what I'm after in general.
SELECT * FROM FT WITH (NOLOCK)
WHERE
CAST(FT_END_DATE AS DATETIME) + DBO.[dbo.IPC_Convert_Time](FT_END_TIME) BETWEEN #STARTDATETIME AND #ENDDATETIME;
Example 2 - Works:
This one runs, but it won't get records from 8/29 because the end dates will be before 12:00:00 on 8/29.
SELECT * FROM FT WITH (NOLOCK)
WHERE
FT_END_DATE BETWEEN #STARTDATETIME AND #ENDDATETIME
AND CAST(FT_END_DATE AS DATETIME) + DBO.[dbo.IPC_Convert_Time](FT_END_TIME) BETWEEN #STARTDATETIME AND #ENDDATETIME;
I suppose I could do one where I split apart my paramters and check that the end time is between the time portion of the parameters as well, but that seems to be a step in the wrong direction. The error seems to only appear when there is no other usage of FT_START_DATE or FT_END_DATE in the where clause.
The time converting function works fine in every scenario I have created. I have even tried Example 2 with parameters that would give it 100% overlap with the data covered by Example 1 in case there was bad data causing the error, but it runs fine.
I also don't know exactly where the error is occurring, because it only references the line the select statement begins on, and not the actual location in the code.
Why does it behave like this?
UPDATE:
TIMEFROMPARTS is not available because this is on SQL Server 2008
If I understand this correctly, this can be done much simpler:
Try this:
DECLARE #d DATE=GETDATE();
DECLARE #t TIME=GETDATE();
SELECT #d;
SELECT #t;
SELECT CAST(#d AS datetime)+CAST(#t AS datetime);
A pure date and a pure time can simply be added to combine them...
UPDATE Read your question again...
Try this
SELECT FT_END_DATE
,FT_END_TIME
,CAST(FT_END_DATE AS DATETIME) + DBO.[dbo.IPC_Convert_Time](FT_END_TIME) AS CombinedTime
,*
FROM FT
to see if your attempt is doing the right thing.
If yes, it might help to create a CTE and do the filter on the named column.
Sometimes the engine does not work the order you would expect this.
As CTEs are fully inlined it is quite possible, that this will not help...
SQL Server is well knwon for bringing up such errors, because a type check happens before a conversion took place...
It might be an idea to use the given SELECT with INTO #tbl to push the result set into a new table and do your logic from there...

How to cache stored procedure results to retrieve the results faster?

I have a stored procedure which takes a lot of time (around 5 minutes) to execute. This stored procedure fills up a table. Now I am retrieving the data from that table. I have created a job to execute this stored procedure every 15 minutes. But while the stored procedure is in execution, my table is empty and the front end shows no results at that time. My requirement is to show data at the front end side all the time.
Is there a way to cache the stored procedure results and use that result while the stored procedure executes?
Here is my stored procedure,
BEGIN
declare #day datetime
declare #maxdate datetime
set #maxdate = getdate()
set #day = Convert(Varchar(10),DATEADD(week, DATEDIFF(day, 0, getdate())/7, 0),110)
truncate table tblOpenTicketsPerDay
while #day <= #maxdate
begin
insert into tblOpenTicketsPerDay
select convert(varchar(20),datename(dw,#day)) day_name, count(*) Open_Tickets from
(select [status], createdate, closedate
FROM OPENROWSET('MSDASQL','DSN=SQLite','Select * from tickets') AS a
where createdate <= #day
except
select [status], createdate, closedate
FROM OPENROWSET('MSDASQL','DSN=SQLite','Select * from tickets') AS a
where closedate <= #day and [status] = 'closed') x
set #day = #day + 1
end
END
Any ideas will be helpful.
Thanks.
If I have understood correct then your main concern is: your stored procedure empties the table and then fills it up and since it takes time, your application have no data show.
In that case, you can have a secondary/auxiliary clone table; say tblOpenTicketsPerDay_clone and have your stored procedure fill that table instead like
insert into tblOpenTicketsPerDay_clone
select convert(varchar(20),datename(dw,#day)) day_name,
count(*) Open_Tickets from
That way your application will always have data to display since main table has the data. Once, the clone table is done filling up then transfer the same data to main table saying
delete from tblOpenTicketsPerDay;
insert into tblOpenTicketsPerDay
select * from tblOpenTicketsPerDay_clone;
No, but the problem is not caching, it isa totally bad approach to generate the data.
Generate new data into a temporary table, then MERGE The results (using the merge keyword) into the original table.
No sense in deleting the data first. That is a terrible design approach.

Update XML node (in an XML column) in SQL Server 2005 with another column value in the same row

I have a temp table with an XML column (XMLColumn) and a VARCHAR column (ABCColumn).
I am trying to replace the value of a particular XML node within XMLColumn with the value that is in ABCColumn of the same row. I need to do this for every row within the temp table. Is this possible to do without a cursor that would hold the replacement value for each fetch?
I have tried doing an update to the temp table using
XmlColumn.modify('replace value of ... with ...')
but I do not have a variable in this case. I need to get the value of a XYZColumn and use it as the replacement value. Every example I have seen either uses a variable or a hardcoded value - not a column value of the same row.
Also, I am using SQL Server 2005. Does anyone have any ideas?
Like This:
UPDATE YourTable
SET xml_col.modify(
'replace value of (/root/val/text())[1] with sql:column("val_col")'
)
(thanks to Andromar; I just edited his answer and used his SQLFiddle, (which works for this one too.))
EDIT: I voted for RBarryYoung's answer, use that instead!
Only way I can think of is a cursor:
declare cur_t cursor for (select id, val_col from YourTable)
declare #id int
declare #val int
open cur_t
fetch cur_t into #id, #val
while ##fetch_status = 0
begin
update YourTable
set xml_col.modify(
'replace value of (/root/val/text())[1] with sql:variable("#val")')
where id = #id
fetch cur_t into #id, #val
end
close cur_t
deallocate cur_t
Example at SQL Fiddle.

TimeStamp in sql

I have a table named Table1 which contains an ID and TimeStamp.
Table structure
ID TimeStamp
1 0x0000000000047509
But when I compare the combination of these fields, it always shows false. What is the reason for this?
My Query is :
DECLARE #ID int
DECLARE #TimeStamp timestamp
SET #ID = 1
SET #TimeStamp = 0x0000000000047509
If EXISTS(SELECT 1 FROM Table1 WHERE ID = #ID AND TimeStamP = #TimeStamp)
BEGIN
SELECT 1 AS RetVal
END
ELSE
BEGIN
SELECT -1 AS RetVal
END
This will simply work in a Query analyzer.But this will not work in a stored Procedure. Any solution for this?
If I recall, TimeStamp in SQL server is not actually a time stamp but is intended for mostly internal use (I used to use TimeStamps for last updated type fields in MySQL but thats not the right type in SQL Server it seems). I believe you will just want to use a datetime or datetime2 data type depending on the accuracy you want.
Here is a link to the choices available: http://msdn.microsoft.com/en-us/library/ms186724.aspx
It should work, I have tried it myself and it worked fine. I ran the following from an SP and it output OK.
DECLARE #t timestamp
SET #t = 0x00000000000055F5
IF EXISTS(SELECT 1 FROM dbo.[User] WHERE [Timestamp]=#t AND UserId=10)
BEGIN
PRINT 'OK'
END
Maybe your timestamp has changed before the SP runs. The timestamp changes every time you insert or update the row. Really rowversion is a better name for it IMHO.
Good resrouces: timestamp and Timestamps vs Datetime data types

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