TSQL DATETIME ISO 8601

Question

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:

Answer 1

For ISO 8601 format for Datetime & Datetime2, below is the recommendation from SQL Server. It does not support basic ISO 8601 format for datetime(yyyyMMddThhmmss).

DateTime

YYYY-MM-DDThh:mm:ss[.mmm]

YYYYMMDD[ hh:mm:ss[.mmm]]

Examples:

1. 2004-05-23T14:25:10

2. 2004-05-23T14:25:10.487

Datetime2

YYYY-MM-DDThh:mm:ss[.nnnnnnn]

YYYY-MM-DDThh:mm:ss[.nnnnnnn] Examples:

1. 2004-05-23T14:25:10

2. 2004-05-23T14:25:10.8849926

You can convert them using 126 option

--Datetime

DECLARE @table Table(ExtendedDate DATETIME, BasicDate Datetime)

DECLARE @ExtendedDate VARCHAR(30) = '2020-07-01T08:39:17' , @BasicDate VARCHAR(30) = '2009-01-23T10:53:21.000'

INSERT INTO @table(ExtendedDate, BasicDate)
SELECT convert(datetime,@ExtendedDate,126) ,convert(datetime,@BasicDate,126)

SELECT * FROM @table
go

-- Datetime2

DECLARE @table Table(ExtendedDate DATETIME2, BasicDate Datetime2)

DECLARE @ExtendedDate VARCHAR(30) = '2000-01-14T13:42:00.0000000' , @BasicDate VARCHAR(30) = '2009-01-23T10:53:21.0000000'

INSERT INTO @table(ExtendedDate, BasicDate)
SELECT convert(datetime2,@ExtendedDate,126) ,convert(datetime2,@BasicDate,126)

SELECT * FROM @table
go

Datetime

+-------------------------+-------------------------+
|      ExtendedDate       |        BasicDate        |
+-------------------------+-------------------------+
| 2020-07-01 08:39:17.000 | 2009-01-23 10:53:21.000 |
+-------------------------+-------------------------+

Datetime2

+-----------------------------+-----------------------------+
|        ExtendedDate         |          BasicDate          |
+-----------------------------+-----------------------------+
| 2000-01-14 13:42:00.0000000 | 2009-01-23 10:53:21.0000000 |
+-----------------------------+-----------------------------+