I have been given a specification that requires the ISO 8601 date format, does any one know the conversion codes or a way of getting these 2 examples:

ISO 8601 Extended Date 2000-01-14T13:42Z 
ISO 8601 Basic Date 20090123T105321Z

Best Solution

When dealing with dates in SQL Server, the ISO-8601 format is probably the best way to go, since it just works regardless of your language and culture settings.

In order to INSERT data into a SQL Server table, you don't need any conversion codes or anything at all - just specify your dates as literal strings

INSERT INTO MyTable(DateColumn) VALUES('20090430 12:34:56.790')

and you're done.

If you need to convert a date column to ISO-8601 format on SELECT, you can use conversion code 126 or 127 (with timezone information) to achieve the ISO format.

SELECT CONVERT(VARCHAR(33), DateColumn, 126) FROM MyTable

should give you: