Datetime conversion error for 1 sql server, but not another

Question

I've got 2 servers running SQL Server 2008, and I have the following query:

SELECT cast('13/1/2011' as datetime)

If I execute this query on Server A I get the result:

2011-01-13 00:00:00.000

However, if I execute this on Server B I get the result:

The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.

I believe this to be a UK/US date format issue as I don't get an error with 12/1/2011 but it does return 2011-12-01 00:00:00.000

How can I get Server B to get the same result as Server A? What setting needs to be changed and where?

Answer 1

It is the language setting of the login that controls how these ambiguous date formats are interpreted (though this can be overridden with an explicit SET DATEFORMAT statement).

The DEFAULT_LANGUAGE can be changed via ALTER LOGIN

Answer 2

Even better, don't rely on the SET DATEFORMAT or DEFAULT_LANGUAGE settings to ensure your date conversions work as expected. In SQL Server one should always—as a matter of best practice—either use a neutral format, or use an explicit format specifier, no matter what language settings are in use or what your dates look like. Try the following on both servers and you will have no problem.

• Date neutral format: Convert(datetime, '20110113')
• Date neutral format: Convert(datetime, '2011-01-13T00:00:00')
• Explicit format specifier: Convert(datetime, '13/1/2011', 103) - see SQL Server Books Online: Cast and Convert for details.