While updating a datatime column in a table from another table, i noticed that mnilliseconds value are not shown.. instead it is rounded and the value is updated to nearest seconds.
Example :
Original Value: 2008-06-26 14:06:36.643
Updated Value : 2008-06-26 14:07:00
Please help me getting the actual value including milliseconds
In the case where you're doing a straight update of a datetime in one table with one from another table (i.e. no fiddling with the value), then it sounds like the datatype in the table being updated is not the same.
i.e. in SQL Server world, it could be that you are using SMALLDATETIME column in the table being updated, but a DATETIME field in the table being copied from. SMALLDATETIME is only accurate to the second and so would show this behaviour
In SQL Server;
SELECT CAST('2008-06-26 14:06:36.643' AS SMALLDATETIME)
> 2008-06-26 14:07:00
So the destination table column is probably SMALLDATETIME (or your casting in the query).
Related
I have 3 tables in the database that I'm working on. Out of 3, two of the tables have columns that include dates. When I checked the information schema of the columns I found that dates have the wrong data type. If you see the picture below, the highlighted columns should be stored as DATE data type.
So, I used the following query to change their data type from varchar to DATE:
ALTER TABLE [dbo].[Customer]
ALTER COLUMN DOB DATE;
ALTER TABLE [dbo].[Transactions]
ALTER COLUMN tran_date DATE;
The error that I get is:
Conversion failed when converting date and/or time from character string.
Please let me know how I can fix this error. Thanks!
What you can do is update the value using try_convert() first and then alter the column name. Note: This will set any invalid values to NULL.
update customer
set dob = try_convert(date, dob);
alter table customer alter column dbo date;
If you want to see the bad values, then before you change the table, run:
select c.*
from customer c
where try_convert(date, dob) is null and dob is not null;
You may have other ideas on how to fix the values.
You can't change from varchar to date or time or datetime by altering the column. Why? Because SQL Server does not know if the field contains '1/1/2020' or 'My dog is cute'. You will have to rebuild the table with the proper data types and then CAST() or CONVERT() the values to a true date time.
Underneath the hood, this makes more sense. A char/varchar uses one byte per character. nchar/nvarchar uses 2 bytes per character. A datetime is a number, not a character. This means you need a routine that changes this into the correct number. If you want to get deeper, the number is the number of ticks (nanoseconds) since midnight on January 1, 0001 in the Gregorian Calendar. More info.
I am using Microsoft SQL Server Management Studio to manipulate Public transport system database.
I have a table in database named 'dbo.tblStop_times', two columns of which should be of data type time. At the moment, they are both nvarchar and they have data stored in a pattern like this - "07:39:00" (without quotes)
I had same question with date columns as well, but found a solution for that on stackoverflow just few hours back.
Below works fine for conversion of nvarchar column to date column.
ALTER TABLE tblCalendar ALTER COLUMN [start_date] DATE NOT NULL;
I am not sure if what I want is achievable or not, because the above mention conversion works just fine, I assume it might be possible.
What I have atm is - nvarchar(8), what I want it to be is sql time data type, something like hh:mm:ss [and if possible - without trailing nnnnnn - nanoseconds component]
You should be able to do:
ALTER TABLE tblStop_times ALTER COLUMN start_time TIME NOT NULL;
Here is a rextester.
EDIT:
If you don't have valid time values, then you have a problem. You should first look for the values:
select col
from tblStop_times
where try_convert(time, col) is null;
This will show you the values that cannot be converted. If you like, you can NULL them out so the alter will work:
update tblStop_times
set col = NULL
where try_convert(time, col) is null;
How do i combine 2 column using SQL server 2005 ?
Problem is that The DateTime is stored in 1 column and the milliseconds is stored in another column.
I want to add the Milliseconds onto DateTime column to give it a more accurate DateTime.
I need to use this DateTime to query record accurate to milliseconds.
Any idea?
I need to replace DateTime with the added values.
SELECT *
FROM TABLENAME
WHERE [DateTime] >= '2011-04-12 12:00:00 AM'
AND [DateTime] <= '2011-05-25 3:35:04 AM'
and run the query.
Well, first solve your problem:
SELECT DATEADD(millisecond,<milliscolumn>,<datetimecolumn>) from <table>
And then file a bug report that these should just be stored in one column anyway.
You can do this, based on your sample query, but note that this destroys the possibility of the server being able to use an index:
SELECT * FROM TABLENAME WHERE
DATEADD(millisecond,[MillisecondColumn],[DateTime]) between
'2011-04-12T12:00:00' AND '2011-05-25T03:35:04'
If this is a large table, then indexes may be important. If you can't alter whatever's populating this data, you might want to add this calculation as a persisted computed column to this table, and then index and query against that.
Note that I've replaced your two comparisons with a single BETWEEN, and also adjusted the datetime strings so that they're not affected by regional settings.
SELECT (ColumnA + ColumnB) AS ColumnZ
FROM Table
might solve your problem.
please tell me how to show the value of timestamp field of a table in datetime format (human understandable). and also how to use it in comparison while querying it.
Thanks
This can't be done. The TIMESTAMP datatype is misnamed - the name has been deprecated in favour of ROWVERSION in SQL 2008, which is a much clearer name.
TIMESTAMP stores an incrementing value which changes every time a row is updated.
If you want last updated dates stored against each row, you will need to add a DATETIME or SMALLDATETIME to your table and update it with the current date on each update.
You mean timestamp data type I think - http://msdn.microsoft.com/en-us/library/ms182776%28v=SQL.90%29.aspx
You can't convert it to datetime. According to the documentation in the link above :
> The timestamp data type is just an incrementing number and does not preserve a date or a time. To record a date or time, use a datetime data type.
The question
Is it possible to ask SSIS to cast a value and return NULL in case the cast is not allowed instead of throwing an error ?
My environment
I'm using Visual Studio 2005 and Sql Server 2005 on Windows Server 2003.
The general context
Just in case you're curious, here is my use case. I have to store data coming from somewhere in a generic table (key/value structure with history) witch contains some sort of value that can be strings, numbers or dates. The structure is something like this :
table Values {
Id int,
Date datetime, -- for history
Key nvarchar(50) not null,
Value nvarchar(50),
DateValue datetime,
NumberValue numeric(19,9)
}
I want to put the raw value in the Value column and try to put the same value
in the DateValue column when i'm able to cast it to Datetime
in the NumberValue column when i'm able to cast it to a number
Those two typed columns would make all sort of aggregation and manipulation much easier and faster later.
That's it, now you know why i'm asking this strange question.
============
Thanks in advance for your help.
You could also try a Derived Column component and test the value of the potential date/number field or simply cast it and redirect any errors as being the NULL values for these two fields.
(1) If you just simply cast the field every time with a statement like this in the Derived Column component: (DT_DATE)[MYPOTENTIALDATE] - you can redirect the rows that fail this cast and manipulate the data from there.
OR
(2) You can do something like this in the Derived Column component: ISNULL([MYPOTENTIALDATE]) ? '2099-01-01' : (DT_DATE)[MYPOTENTIALDATE]. I generally send through '2099-01-01' when a date is NULL rather than messing with NULL (works better with Cubes, etc).
Of course (2) won't work if the [MYPOTENTIALDATE] field comes through as other things other than a DATETIME or NULL, i.e., sometimes it is a word like "hello".
Those are the options I would explore, good luck!
In dealing with this same sort of thing I found the error handling in SSIS was not specific enough. My approach has been to actually create an errors table, and query a source table where the data is stored as varchar, and log errors to the error table with something like the below. I have one of the below statements for each column, because it was important for me to know which column failed. Then after I log all errors, I do a INSERT where I select those records in SomeInfo that do not have an errors. In your case you could do more advanced things based on the ColumnName in the errors table to insert default values.
INSERT INTO SomeInfoErrors
([SomeInfoId]
,[ColumnName]
,[Message]
,FailedValue)
SELECT
SomeInfoId,
'PeriodStartDate',
'PeriodStartDate must be in the format MM/DD/YYYY',
PeriodStartDate
FROM
SomeInfo
WHERE
ISDATE(PeriodStartDate) = 0 AND [PeriodStartDate] IS NOT NULL;
Tru using a conditional split and have the records where the data is a date go along one path and the other go along a different path where they are updated to nullbefore being inserted.