Date conversion and culture: Difference between DATE and DATETIME

Question

I\'ve written a lot of answers about date or datetime conversions from strings. Living in a german speaking country, I\'m used to deal with non

Answer 1

(Started out as a comment, but...) To add some more data to marc_s's answer, datetime will also fail with yyyy-mm-dd HH:MM:ss - So

SET LANGUAGE GERMAN;
DECLARE @dateTimeFailes DATETIME ='2017-01-13 00:00:00';

Will result with the same error. However, Once you replace the space between the Date and Time parts with a T, SQL Server will suddenly understand the format -

SET LANGUAGE GERMAN;
DECLARE @dateTime DATETIME ='2017-01-13T00:00:00';

Will work as expected.

Here is a quick list of acceptable and unacceptable formats:

SET LANGUAGE GERMAN;
-- Correct 
DECLARE @date DATE ='2017-01-13';
DECLARE @dateTime DATETIME ='2017-01-13T00:00:00'; 
DECLARE @dateTimeDateOnly DATETIME ='20170113';

-- Incorrect
DECLARE @WrongFormatDateTime DATETIME ='2017-01-13 00:00:00'; 
DECLARE @WrongFormatDate DATETIME ='2017-01-13';