Error Converting NVARCHAR to DATETIME - sql-server

I create a temp table
CREATE TABLE #Test(theDate DATETIME)
I use this query to insert data into the temp table
INSERT INTO #Test VALUES(CONVERT(NVARCHAR, '2016-09-30' 21))
It works on one database (SQL Server 2005), but gives error on another (SQL Server 2008). I can't remember the exact error, but it has something to do with 'Error converting NVARCHAR TO DATETIME'
Why is working on one database, but not another? Is there a special property to enforce error on mismatched type? I can't find information anywhere.


There are several problems:
You use CONVERT to convert a string to a string while you want a DATE
You use NVARCHAR without a length (which is 1 by default) Bad habit to kick
There is a comma missing after the date literal
You are using 21 which is the format with a 2-digit-year Details here
Better was this
SELECT CONVERT(DATETIME, '2016-09-30', 121)
But even better was to avoid conversions at all.
In your case use Details here
unseparated: INSERT INTO #Test VALUES('20160930')
ODBC (my favorite): INSERT INTO #Test VALUES({d'2016-09-30'})
UPDATE
I cannot check this, no such versions installed, but I'm quite sure, that different default culture / language and implicit error correction leads to this behaviour...
On my SQL Server 2012 instance all of them work fine. The obvious format error (21 instead of 121) is corrected implicitly. The second obvious error (conversion to a 1-char-string) is corrected as well. Lower versions deal with this differently (probably).
If possible, try these lines on your servers...
SET LANGUAGE US_ENGLISH; --MDY
SELECT CONVERT(NVARCHAR, '2016-09-30', 21)
SET LANGUAGE GERMAN; --DMY
SELECT CONVERT(NVARCHAR, '2016-09-30', 21)
SET LANGUAGE JAPANESE; --YMD
SELECT CONVERT(NVARCHAR, '2016-09-30', 21)
The literal date format YYYY-MM-DD, even as this is short ISO8601, is not sure in all situations. That's why one should use culture independant formats always...


You can try this if it is a problem related to language
declare #language as varchar(100)
SELECT #language= ##LANGUAGE
SET LANGUAGE us_english
--... your code...
SET LANGUAGE #language

Related

sql server convert function behave differently on different machine

When I run this query on one machine it works perfectly:
select convert(datetime, '2021-01-18 00:00:00.000')
But in another machine, I get an out of range error:
The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.

That format is invalid when using certain language and dateformat settings. Example db<>fiddle and another example.
SET DATEFORMAT YDM;
SELECT CONVERT(datetime, '2021-01-18 00:00:00.000');
..or...
SET LANGUAGE BRITISH;
SELECT CONVERT(datetime, '2021-01-18 00:00:00.000');
Both yield:
Msg 242 Level 16 State 3
The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.
You do not need to reinstall SQL Server to fix this, as it's not the installation that is the problem.
The real solution is to always use a safe, unambiguous format - see the links in the "Regional formats" section of Dating Responsibly.
These all succeed, for example:
SET DATEFORMAT YDM;
SELECT CONVERT(datetime, '2021-01-18T00:00:00.000');
SELECT CONVERT(datetime, '20210118 00:00:00.000');
SELECT CONVERT(datetime, '20210118');
...and...
SET LANGUAGE BRITISH;
SELECT CONVERT(datetime, '2021-01-18T00:00:00.000');
SELECT CONVERT(datetime, '20210118 00:00:00.000');
SELECT CONVERT(datetime, '20210118');
If you can't control the format of the string, then another option is to manually apply these settings first (this should work on whatever machine it's currently failing for you):
SET DATEFORMAT YMD;
SET LANGUAGE us_english;
SELECT CONVERT(datetime, '2021-01-18 00:00:00.000');
This is obviously not the optimal solution.
The issue may also be that the login connecting to the server with wrong results has their default language set to something other than the default US English (more than half of the languages SQL Server supports interpret yyyy-mm-dd as yyyy-dd-mm, for reasons I will never understand).
If this is the case, you may be able to fix this login...
ALTER LOGIN [login name] WITH DEFAULT_LANGUAGE = [us_english];
...but unless you are switching from british, this will have other consequences for them, such as language of warnings and errors, interpretation of other data like numeric, and so on. It also won't last if the login changes their setting back, and it won't affect any future logins that are created with a non-default language (or any logins that later change in the "wrong" direction).
So I still feel like fixing the way the ambiguous string is interpreted is not the answer.
In the comment you say you have code that does this:
WHERE datetime_col >= '2018-01-12'
In which case you can either:
(a) convert to datetime with the 120 style, overriding regional/language settings:
WHERE datetime_col >= CONVERT(datetime, '2018-01-12', 120)
(b) convert to date, which doesn't care about regional/language settings:
WHERE datetime_col >= CONVERT(date, '2018-01-12')
(c) I still think the best (and easiest!) answer is to simply not use an ambiguous format that requires workarounds and/or every login to be created a specific way and never override session settings:
WHERE datetime_col >= '20180112'

Check data type format of every value of a column in SQL Server

I have a table_1 that has column dob which has datatype nvarchar(max). Now I want to check every date whether it is in datetime format or not.
The dates which are in datetime format should be copied to table_2 that has column with a datatype of datetime.
Any help how can I do this?

If you are using SQL Server 2012 or later, then TRY_CONVERT can help here:
SELECT *
FROM yourTable
WHERE TRY_CONVERT(datetime, dob) IS NULL;
This would return every record from your table where the dob text field is in some format which SQL Server cannot natively convert to a datetime.

This will insert all the strings can be converted into Table_2
INSERT INTO Table_2 (DateTimeColumn)
SELECT dob
FROM Table_1
WHERE TRY_CAST(dob AS DATETIME) IS NOT NULL;

It is a very bad habit to store datetime values in a string. The reason why: Date-Time formats differ around the world and depend on your system's culture settings. Even worse, some format depend on a given language. Try this out:
SET LANGUAGE ENGLISH; --try with GERMAN to see the effect on "Decemeber"
SET DATEFORMAT ymd; --try with "ydm" or "dmy"
DECLARE #tbl TABLE(dob NVARCHAR(MAX));
INSERT INTO #tbl VALUES('blah') --just a wrong value
,('20201231') --ISO, "unseparated YMD-format (see CONVERT with 112)
,('2020-12-31') --ISO8601
,('2020-31-12') --European with leading year
,('12-31-2020') --USA (see CONVERT with 110)
,('31-12-2020') --European (see CONVERT with 113)
,('31 December 2020') --language dependant (see CONVERT with 113), try with German "Dezember"
,('2020-02-30'); --Invalid, there's no 30th of February
SELECT t.dob --Your value
,[cast] = TRY_CAST(t.dob AS DATETIME) --CAST relies on the system's settings (might work on your machine but can break on a customer's machine
,[convert] = TRY_CONVERT(DATETIME, t.dob, 112) --CONVERT allows to use the style paramter, better than CAST, but more strict
,[parse] = TRY_PARSE(t.dob AS DATETIME USING 'en-US') --Parsing allows to mention the culture. You do not need to specify the language as a general setting
,[xmlCast] = CAST(t.dob AS XML).value('. cast as xs:date?','datetime') --Works below v2012, but can deal with ISO8601 only.
FROM #tbl t;
Play with the settings
You can use GERMAN instead of ENGLISH. The entry with December will not work any more. You can change the general date format to any combination of ymd and find, that some formats stop to work while others start to work.
TRY_CAST, TRY_CONVERT and TRY_PARSE will need a version of v2012 or higher.
If you are running an older system you should upgrade ( :-) ). The only chance with an older system is a XML hack, but this is very tightly bound to ISO8601.
Finally: For your next question, please try to add more information. State some of your input values, mention your RDBMS with version and try to set up a mockup with DDL and INSERT (look what I've done above).
Hint: Very dangerous...
Try to insert a value like 2020-05-06 and you will find, that some styles read this as the 5th of June, while others return the 6th of May. Returning wrong values is worse than returning NULL or throwing an error...
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SQL DateTime Inserted Incorrectly From VB.NET

Have a table I'm logging information from a .NET program into.
The VB.NET app explicity dictates the format of the DATETIME string like below
responsedt = Date.Now.ToString("yyyy-MM-dd HH:mm:ss.fff")
I then pass this into an INSERT statement that updates my table, however even though the entire setup of the SQL Server is en-GB (British English) the DateTime has gone in the following format:
2019-09-05 19:09:34.823
This was done yesterday so actually should be
2019-05-09 19:09:34.823
The day and month should be switched around, I have tried performing an update on the table post process to get it to update using the following code
FORMAT (xa.daterequested, 'yyyy-dd-MM HH:MM:ss.fff', 'en-gb')
How while this works in a SELECT statement it doesn't seem to work when I do the UPDATE statement.
It is not ideal to have to update all the records dates after the initial INSERT so a solution to either the .NET side of the issue or the SQL would be appreciated as its pickling my head.

You have 2 options to prevent the error from happening again:
Keep dates as date/time data types instead of converting them to strings.
Use formats that are not language or settings dependent. In SQL Server these would be YYYYMMDD hh:mm:ss.msss OR YYYY-MM-DDThh:mm:ss.mss (notice the T between date and time)
To correct the dates already inserted you could use the format codes in the CONVERT function.
UPDATE t SET
daterequested = STUFF( STUFF( StringDate, 5, 0, SUBSTRING(StringDate,7,2)), 9, 2, '')
FROM YourTable t
CROSS APPLY( SELECT CONVERT( varchar(25), '20190905 19:09:34.823', 121) AS StringDate) AS x;

Converting NVARCHAR(255) to DATE

I'm trying to transfer some old SQL Server data using Excel into SQL Server. It seems that Import/Export Data application automatically sets most data columns to NVARCHAR(255). Problem I have, is one of my columns is supposed to be a DATE type, but all data in it looks like this 18.08.2000 14:48:15.
So, when I try to use this query:
SELECT CONVERT(Date, DATE_TIME, 113)
FROM someTable
I get this error:
Msg 9807, Level 16, State 0, Line 1
The input character string does not follow style 113, either change the input character string or use a different style.
None of the [styles] from CAST and CONVERT (Transact-SQL) are working in my case.
Any advise or help is greatly appreciated.
SOLVED:
UPDATE myTable
SET columnName = CONVERT(NVARCHAR(255),CONVERT(SMALLDATETIME, columnName,105))
ALTER TABLE myTable
ALTER COLUMN columnName SMALLDATETIME

So, if it will ever become useful to anyone, this is the exact code that changes datatype NVARCHAR to DATETIME:
UPDATE myTable
SET columnName = CONVERT(NVARCHAR(255),CONVERT(SMALLDATETIME, columnName,105))
ALTER TABLE myTable
ALTER COLUMN columnName SMALLDATETIME

As far as I can tell - style no. 103 (British/French) should work - no?
DECLARE #input NVARCHAR(255)
SET #input = '18.08.2000 14:48:15'
SELECT CONVERT(DATETIME, #input, 103)
Gives me the output of:
2000-08-18 14:48:15.000
which seems pretty reasonable, no??

If you are using SQL Server 2012, try:
PARSE(Date AS datetime USING 'en-GB')
Or if that doesn't work, try:
PARSE(Date AS datetime USING 'Et-EE')
The Estonian culture specifically uses '.' as a date separator (d.MM.yyyy H:mm:ss) so it should work.
(Both seem to work fine on SQL Fiddle)

Sql Server string to date conversion

I want to convert a string like this:
'10/15/2008 10:06:32 PM'
into the equivalent DATETIME value in Sql Server.
In Oracle, I would say this:
TO_DATE('10/15/2008 10:06:32 PM','MM/DD/YYYY HH:MI:SS AM')
This question implies that I must parse the string into one of the standard formats, and then convert using one of those codes. That seems ludicrous for such a mundane operation. Is there an easier way?

Try this
Cast('7/7/2011' as datetime)
and
Convert(DATETIME, '7/7/2011', 101)
See CAST and CONVERT (Transact-SQL) for more details.

Run this through your query processor. It formats dates and/or times like so and one of these should give you what you're looking for. It wont be hard to adapt:
Declare #d datetime
select #d = getdate()
select #d as OriginalDate,
convert(varchar,#d,100) as ConvertedDate,
100 as FormatValue,
'mon dd yyyy hh:miAM (or PM)' as OutputFormat
union all
select #d,convert(varchar,#d,101),101,'mm/dd/yy'
union all
select #d,convert(varchar,#d,102),102,'yy.mm.dd'
union all
select #d,convert(varchar,#d,103),103,'dd/mm/yy'
union all
select #d,convert(varchar,#d,104),104,'dd.mm.yy'
union all
select #d,convert(varchar,#d,105),105,'dd-mm-yy'
union all
select #d,convert(varchar,#d,106),106,'dd mon yy'
union all
select #d,convert(varchar,#d,107),107,'Mon dd, yy'
union all
select #d,convert(varchar,#d,108),108,'hh:mm:ss'
union all
select #d,convert(varchar,#d,109),109,'mon dd yyyy hh:mi:ss:mmmAM (or PM)'
union all
select #d,convert(varchar,#d,110),110,'mm-dd-yy'
union all
select #d,convert(varchar,#d,111),111,'yy/mm/dd'
union all
select #d,convert(varchar,#d,12),12,'yymmdd'
union all
select #d,convert(varchar,#d,112),112,'yyyymmdd'
union all
select #d,convert(varchar,#d,113),113,'dd mon yyyy hh:mm:ss:mmm(24h)'
union all
select #d,convert(varchar,#d,114),114,'hh:mi:ss:mmm(24h)'
union all
select #d,convert(varchar,#d,120),120,'yyyy-mm-dd hh:mi:ss(24h)'
union all
select #d,convert(varchar,#d,121),121,'yyyy-mm-dd hh:mi:ss.mmm(24h)'
union all
select #d,convert(varchar,#d,126),126,'yyyy-mm-dd Thh:mm:ss:mmm(no spaces)'

In SQL Server Denali, you will be able to do something that approaches what you're looking for. But you still can't just pass any arbitrarily defined wacky date string and expect SQL Server to accommodate. Here is one example using something you posted in your own answer. The FORMAT() function and can also accept locales as an optional argument - it is based on .Net's format, so most if not all of the token formats you'd expect to see will be there.
DECLARE #d DATETIME = '2008-10-13 18:45:19';
-- returns Oct-13/2008 18:45:19:
SELECT FORMAT(#d, N'MMM-dd/yyyy HH:mm:ss');
-- returns NULL if the conversion fails:
SELECT TRY_PARSE(FORMAT(#d, N'MMM-dd/yyyy HH:mm:ss') AS DATETIME);
-- returns an error if the conversion fails:
SELECT PARSE(FORMAT(#d, N'MMM-dd/yyyy HH:mm:ss') AS DATETIME);
I strongly encourage you to take more control and sanitize your date inputs. The days of letting people type dates using whatever format they want into a freetext form field should be way behind us by now. If someone enters 8/9/2011 is that August 9th or September 8th? If you make them pick a date on a calendar control, then the app can control the format. No matter how much you try to predict your users' behavior, they'll always figure out a dumber way to enter a date that you didn't plan for.
Until Denali, though, I think that #Ovidiu has the best advice so far... this can be made fairly trivial by implementing your own CLR function. Then you can write a case/switch for as many wacky non-standard formats as you want.
UPDATE for #dhergert:
SELECT TRY_PARSE('10/15/2008 10:06:32 PM' AS DATETIME USING 'en-us');
SELECT TRY_PARSE('15/10/2008 10:06:32 PM' AS DATETIME USING 'en-gb');
Results:
2008-10-15 22:06:32.000
2008-10-15 22:06:32.000
You still need to have that other crucial piece of information first. You can't use native T-SQL to determine whether 6/9/2012 is June 9th or September 6th.

SQL Server (2005, 2000, 7.0) does not have any flexible, or even non-flexible, way of taking an arbitrarily structured datetime in string format and converting it to the datetime data type.
By "arbitrarily", I mean "a form that the person who wrote it, though perhaps not you or I or someone on the other side of the planet, would consider to be intuitive and completely obvious." Frankly, I'm not sure there is any such algorithm.

Use this:
SELECT convert(datetime, '2018-10-25 20:44:11.500', 121) -- yyyy-mm-dd hh:mm:ss.mmm
And refer to the table in the official documentation for the conversion codes.

For this problem the best solution I use is to have a CLR function in Sql Server 2005 that uses one of DateTime.Parse or ParseExact function to return the DateTime value with a specified format.

Short answer:
SELECT convert(date, '10/15/2011 00:00:00', 101) as [MM/dd/YYYY]
Other date formats can be found at SQL Server Helper > SQL Server Date Formats

Took me a minute to figure this out so here it is in case it might help someone:
In SQL Server 2012 and better you can use this function:
SELECT DATEFROMPARTS(2013, 8, 19);
Here's how I ended up extracting the parts of the date to put into this function:
select
DATEFROMPARTS(right(cms.projectedInstallDate,4),left(cms.ProjectedInstallDate,2),right( left(cms.ProjectedInstallDate,5),2)) as 'dateFromParts'
from MyTable

The most upvoted answer here are guravg's and Taptronic's. However, there's one contribution I'd like to make.
The specific format number they showed from 0 to 131 may vary depending on your use-case (see full number list here), the input number can be a nondeterministic one, which means that the expected result date isn't consistent from one SQL SERVER INSTANCE to another, avoid using the cast a string approach for the same reason.
Starting with SQL Server 2005 and its compatibility level of 90,
implicit date conversions became nondeterministic. Date conversions
became dependent on SET LANGUAGE and SET DATEFORMAT starting with
level 90.
Non deterministic values are 0-100, 106, 107, 109, 113, 130. which may result in errors.
The best option is to stick to a deterministic setting, my current preference are ISO formats (12, 112, 23, 126), as they seem to be the most standard for IT people use cases.
Convert(varchar(30), '210510', 12) -- yymmdd
Convert(varchar(30), '20210510', 112) -- yyyymmdd
Convert(varchar(30), '2021-05-10', 23) -- yyyy-mm-dd
Convert(varchar(30), '2021-05-10T17:01:33.777', 126) -- yyyy-mm-ddThh:mi:ss.mmm (no spaces)

This page has some references for all of the specified datetime conversions available to the CONVERT function. If your values don't fall into one of the acceptable patterns, then I think the best thing is to go the ParseExact route.

Personally if your dealing with arbitrary or totally off the wall formats, provided you know what they are ahead of time or are going to be then simply use regexp to pull the sections of the date you want and form a valid date/datetime component.

If you want SQL Server to try and figure it out, just use CAST
CAST('whatever' AS datetime)
However that is a bad idea in general. There are issues with international dates that would come up. So as you've found, to avoid those issues, you want to use the ODBC canonical format of the date. That is format number 120, 20 is the format for just two digit years.
I don't think SQL Server has a built-in function that allows you to provide a user given format. You can write your own and might even find one if you search online.

convert string to datetime in MSSQL implicitly
create table tmp
(
ENTRYDATETIME datetime
);
insert into tmp (ENTRYDATETIME) values (getdate());
insert into tmp (ENTRYDATETIME) values ('20190101'); --convert string 'yyyymmdd' to datetime
select * from tmp where ENTRYDATETIME > '20190925' --yyyymmdd
select * from tmp where ENTRYDATETIME > '20190925 12:11:09.555'--yyyymmdd HH:MIN:SS:MS

You can easily achieve this by using this code.
SELECT Convert(datetime, Convert(varchar(30),'10/15/2008 10:06:32 PM',102),102)

This code solve my problem :
convert(date,YOUR_DATE,104)
If you are using timestamp you can you the below code :
convert(datetime,YOUR_DATE,104)

dateadd(day,0,'10/15/2008 10:06:32 PM')

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